Matthias Kellner,
Jacob B. Holmes,
Ruben Rodriguez-Madrid,
Florian Viscosi,
Yuxuan Zhang,
Lyndon Emsley,
Michele Ceriotti
- Nuclear Magnetic Resonance (NMR) chemical shifts are powerful probes of local atomic and electronic structure that can be used to resolve the structures of powdered or amorphous molecular solids.
Chemical shift driven structure elucidation depends critically on accurate and fast predictions of chemical shieldings, and machine learning (ML) models for shielding predictions are increasingly used as scalable and efficient surrogates for demanding ab initio calculations. However, the prediction accuracies of current ML models still lag behind those of the DFT reference methods they approximate, especially for nuclei such as 13C and 15N. Here, we introduce \shiftmlthree{}, a deep-learning model thatimproves the accuracy of predictions of isotropic chemical shieldings in molecular solids, and does so while also predicting the full shielding tensor.
On experimental benchmark sets, we find root-mean-squared errors with respect to experiment for ShiftML that approach those of DFT ...
Latest version: v1
Publication date: Jun 16, 2025
Anna Paola Panunzi,
Leonardo Duranti,
Elisabetta Di Bartolomeo,
Jinzhen Huang,
Camelia N. Borca,
Thomas Huthwelker,
Dominika Baster,
Mario El Kazzi,
Marcello Marelli,
Emiliana Fabbri,
Juliana Bruneli Falqueto
- The use of perovskite oxides as bifunctional catalysts for oxygen electrocatalysis is a promising strategy for developing high-performance unified regenerative fuel cells (URFCs), thanks to their highly tunable structure. This work explores the exsolution of well-dispersed nanoparticles containing reduced Pt species from La0.6Sr0.4Fe0.95Pt0.05O3-δ (LSFPt) as an effective approach to design bifunctional catalysts for oxygen electrocatalysis. A 10 h reduction treatment at 500 °C in 5% H2/Ar promotes the exsolution of ~1.2 nm Pt-containing nanoparticles on the surface, increasing oxygen deficiency without compromising the perovskite structure. The resulting catalyst exhibits significantly improved activity for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in alkaline media, with over 2.5-fold performance improvement compared to the as-prepared LSFPt. Electrochemical impedance spectroscopy (EIS), combined ...
Latest version: v1
Publication date: Jun 16, 2025
Divya Suman,
Jigyasa Nigam,
Sandra Saade,
Paolo Pegolo,
Hanna Tuerk,
Xing Zhang,
Garnet Kin-Lic Chan,
Michele Ceriotti
- Traditional atomistic machine learning (ML) models serve as surrogates for quantum mechanical (QM) properties, predicting quantities such as dipole moments and polarizabilities, directly from compositions and geometries of atomic configurations. With the emergence of ML approaches to predict the “ingredients” of a QM calculation, such as the ground state charge density or the effective single-particle Hamiltonian, it has become possible to obtain multiple properties through analytical physics-based operations on these intermediate ML predictions. We present a framework to seamlessly integrate the prediction of an effective electronic Hamiltonian, for both molecular and condensed-phase systems, with PySCFAD, a differentiable QM workflow. This integration facilitates training models indirectly against functions of the Hamiltonian such as electronic energy levels, dipole moments, polarizability, etc. We then use this framework to explore various possible choices within the design ...
Latest version: v1
Publication date: Jun 02, 2025
Rohit Goswami
- The increasing use of high-throughput computational chemistry demands rigorous methods for evaluating algorithm performance. We present a Bayesian hierarchical modeling paradigm (brms/Stan) for analyzing key performance metrics: function evaluations, computation time, and success/failure. This framework accounts for variability across different systems and functionals, providing reliable uncertainty estimates beyond subjective visual assessments or frequentist limitations. We applied this to compare conjugate gradient (CG) and L-BFGS algorithms for the Dimer method's rotation phase (in EON, with/without removal of external rotations) on a benchmark of 500 initial saddle search approximations, analyzing over 2000 runs. Our results show CG rotations generally outperform L-BFGS, exhibiting a statistically credible, small reduction in PES calls and significantly higher odds of successful convergence. Conversely, enabling rotation removal incurred a substantial PES call penalty without ...
Latest version: v1
Publication date: Jun 01, 2025
Yong-Bin Zhuang,
Alfredo Pasquarello
- This entry provides original trajectories of on-the-fly probability enhanced sampling (OPES) and of molecular dynamics simulations and images of nudged-elastic band (NEB) calculation. Jupyter notebooks are provided for a NEB profile, NEB collective variables, free energy surface of the OPES simulations, hole transfer of the OPES simulations, proton transfer mechanisms of of the OPES simulations, water density profiles of MD simulations, radial distribution functions of MD simulations, reweight of Bi-O bonds of OPES simulations, coordination numbers of surface Bi atoms and hydrogen-bond analysis of proton transfer.
Latest version: v2
Publication date: Jun 01, 2025
Sophie Weber,
Andrea Urru,
Nicola Spaldin
- We use symmetry analysis and density functional theory to show that changes in magnetic order at a surface with respect to magnetic order in the bulk can be generically determined by considering local magnetoelectric responses of the crystal. Specifically, analysis of the atomic-site magnetoelectric responses, or equivalently the corresponding local magnetic multipoles, can be used to predict all surface magnetic modifications arising purely from symmetry lowering via termination of the bulk magnetic order. This analysis applies even in materials with no bulk magnetoelectric response or surface magnetization. We then demonstrate our arguments for two example antiferromagnets, metallic CuMnAs and rock-salt NiO. We find that the (010) and (1-10) surfaces of CuMnAs and NiO respectively exhibit a series of antiferroically, as well as roughness-sensitive, ferroically ordered, modifications of the surface magnetic dipole moments, via canting or changes in sublattice magnitude, ...
Latest version: v1
Publication date: May 29, 2025
Fatemeh Haddadi,
Davide Campi,
Flaviano Dos Santos,
Nicolas Mounet,
Louis Ponet,
Nicola Marzari,
Marco Gibertini
- Magnetic materials often exhibit complex energy landscapes with multiple local minima, each corresponding to a self-consistent electronic structure solution. Finding the global minimum is challenging, and heuristic methods are not always guaranteed to succeed. We apply an automated workflow to systematically explore the energy landscape of 194 magnetic monolayers from the Materials Cloud 2D crystals database and determine their ground-state magnetic order. Our approach enables effective control and sampling of orbital occupation matrices, allowing rapid identification of local minima. We reveal a diverse set of self-consistent collinear metastable states, further enriched by Hubbard-corrected energy functionals with U parameters computed from first principles using linear response theory. We categorize the monolayers by their magnetic ordering and highlight promising candidates for applications.
Latest version: v1
Publication date: May 26, 2025
Rohit Goswami,
Maxim Masterov,
Satish Kamath,
Alejandro Peña-Torres,
Hannes Jónsson
- The task of locating first order saddle points on high-dimensional surfaces describing the variation of energy as a function of atomic coordinates is an essential step for identifying the mechanism and estimating the rate of thermally activated events within the harmonic approximation of transition state theory. When combined directly with electronic structure calculations, the number of energy and atomic force evaluations needed for convergence is a primary issue. Here, we describe an efficient implementation of Gaussian process regression (GPR) acceleration of the minimum mode following method where a dimer is used to estimate the lowest eigenmode of the Hessian. A surrogate energy surface is constructed and updated after each electronic structure calculation. The method is applied to a test set of 500 molecular reactions previously generated by Hermez and coworkers [J. Chem. Theory Comput. 18, 6974 (2022)]. An order of magnitude reduction in the number of electronic structure ...
Latest version: v1
Publication date: May 26, 2025
Nicephore Bonnet,
Nicola Marzari
- Understanding the thermodynamics of adsorbates on surfaces is central to many (electro)catalysis applications. In first-principles calculations, additional challenges arise when considering charged adsorbates owing to long-range electrostatic interactions in the in-plane and normal directions. Here, we derive an analytical correction to obtain the energy profiles of individual charged adsorbates on metallic surfaces from finite-cell calculations in periodic boundary conditions. The method is illustrated by calculating the adsorption energy profiles of Li+, Na+, and K+ on graphite from first-principles, highlighting the very slow convergence with system size of the periodic calculations and the need to correctly recover the infinite limit.
In this record, we provide the generic input file used to generate the calculated energies of Fig. 4.
Latest version: v1
Publication date: May 26, 2025
Nicephore Bonnet,
Nicola Marzari
- A first-principles approach for calculating ion separation in solution through 2D membranes is proposed. Ionic energy profiles across the membrane are obtained first, where solvation effects are explicitly simulated by machine-learning molecular dynamics, electrostatic corrections are applied to remove finite-size capacitive effects, and a mean-field treatment of the electrochemical double layer charging is used. Entropic contributions are assessed analytically and through a thermodynamic integration scheme. Ionic separations are then inferred through a microkinetic model of the filtration process, accounting for steady-state charge separation effects across the membrane. The approach is applied to Li+, Na+, K+ sieving through a crown-ether functionalized graphene membrane, with a case study of the mechanisms for a highly selective and efficient extraction of lithium from aqueous solutions.
This record contains the MD trajectories used to generate the energy and free energy profiles of Fig. 4.
Latest version: v1
Publication date: May 26, 2025
Junwen Yin,
Olle Hellman,
Samuel Poncé
- Charge carrier mobilities are critical parameters in halide perovskite solar cells, governing their average carrier velocity under an applied electric field and overall efficiency. Recent advances in first-principles calculations of electron-phonon interactions and carrier mobilities have enabled predictive computations for perovskite solar cells. However, the flexible octahedral frameworks and cationic displacements in these materials challenge the harmonic approximation, leading to significant difficulties in accurately calculating transport properties. To address these issues, we combine temperature-dependent effective potentials with the ab initio Boltzmann transport equations to compute carrier mobilities in a representative lead-free perovskite, CsSnBr₃. At room temperature, the electron/hole Hall mobilities in CsSnBr₃ are 106/256 cm²/Vs when neglecting anharmonic effects and 59/145 cm²/Vs when included. This overestimation of the harmonic approximation arises from the ...
Latest version: v1
Publication date: May 26, 2025
Kurt Irvin Rojas,
Luong Thi Ta,
Shunsuke Naka,
Yoshitada Morikawa,
Ikutaro Hamada
- We present a comprehensive vibrational analysis of hydrogen boride sheet through first-principles calculations, focusing on a variety of local structural configurations including surfaces, edges, and bilayer models - some of which contains vacancy and substitutional defects. A database of vibrational modes and simulated infrared spectra was constructed, revealing distinct spectral features that serve as characteristic fingerprints for different bonding environments. By analyzing mode distributions with respect to coordination environments, we identify the distinct contributions of terminal and bridging hydrogen atoms to specific spectral regions. The results show that structural modifications, such as interlayer stacking and edge termination, have a significant influence on vibrational characteristics, particularly in the intermediate and high frequency regions. The vibrational database enables the precise interpretation of infrared spectra and offers a reliable reference for ...
Latest version: v1
Publication date: May 23, 2025
Shivalika Sharma,
Liviu Chioncel,
Igor Di Marco
- Kagome metals have emerged as pivotal materials in condensed matter physics due to their unique geometric arrangement and intriguing electronic properties. Understanding the origin of magnetism in these materials, particularly in iron rich Fe-Sn binary compounds like Fe₃Sn, holds a significant importance, as they represent potential candidates for permanent magnets with a high Curie temperature and a strong magnetic anisotropy. In the present study, we employ density-functional theory and dynamical mean-field theory to analyze the electronic structure and magnetic properties of Fe₃Sn. Our investigation reveals the presence of several nearly-flat bands and Weyl nodes at low excitation energies. The inclusion of local correlation effects is shown to push these features even closer to the Fermi energy, which may be important for their manipulation via external stimuli. Regarding magnetism, the Hubbard-like interaction leads to an increase of orbital polarization at the expenses of a ...
Latest version: v1
Publication date: May 23, 2025
Naoki Morishita,
Kenshin Komatsu,
Motoharu Kitatani,
Koichi Kusakabe
- The dataset uploaded here records atomic positions, lattices vectors and Python scripts for tight-binding calculations related to the paper entitled "Modulated Dirac bands and integer hopping ratios in a honeycomb lattice of phenalenyl-tessellation molecules." In a family of nanographene called phenalenyl-tessellation molecules (PTMs), two types of zero modes appear: one is uniformly extended over the entire molecule and the other is localized around vacancies. Therefore, it is expected that energy bands reflecting the properties of these two types of zero modes will appear in a honeycomb PTM (H-PTM). In this study, we show that modulated energy gap and the Fermi velocity of Dirac bands appear in H-PTMs and that the effective two-site model has positive integer hopping ratios based on the uniformly extended zero mode and the number of connections between PTMs. Furthermore, we find that the localized zero modes around vacancies can coexist with the modulated Dirac bands. The ...
Latest version: v1
Publication date: May 23, 2025
Debdipto Acharya,
Omar Abou El Kheir,
Simone Marcorini,
Marco Bernasconi
- Phase change materials are the most promising candidates for the realization of artificial synapsis for neuromorphic computing. Different resistance levels corresponding to analogic values of the
synapsis conductance can be achieved by modulating the size of an amorphous region embedded in its crystalline matrix. Recently, it has been proposed that a superlattice made of alternating layers of the phase change compound Sb₂Te₃ and of the TiTe₂ confining material allows for a better control of multiple intermediate resistance states and for a lower drift with time of the electrical resistance of the amorphous phase. In this work, we consider to substitute Sb₂Te₃ with the Ge₂Sb₂Te₅ prototypical phase change compound that should feature better data retention. By exploiting molecular dynamics simulations with a machine learning interatomic potential, we have investigated the crystallization kinetics of Ge₂Sb₂Te₅ nanoconfined in geometries mimicking Ge₂Sb₂Te₅/TiTe₂ superlattices. It ...
Latest version: v1
Publication date: May 23, 2025
Behrang Mohajer,
Chul B. Park,
Markus Bussmann
- This study presents a computational model to enhance the spunbonding drafter's performance. The existing design exhibits a significant risk of fiber breakage. To address this issue, an OpenFOAM computational fluid dynamics (CFD) solver is employed to simulate the airflow over the base geometry and its modified configurations following various design alterations. The collected data are analyzed for predefined optimization objectives: (a) maximize shear drag and thus draw on the filaments, (b) achieve maximum drawing uniformity, and (c) minimize the pressurized air consumption rate. These goals are set to produce more uniform filaments, reduce the breakage risk, and improve energy efficiency. We vary seven design parameters, ran many CFD simulations, and recommend a few enhancements for a drafter based on those. We identify a "braking effect" on the filaments and find that geometry significantly affects the internal airflow and, thus, the drawing process. Based on our findings, we ...
Latest version: v1
Publication date: May 21, 2025
Virginia Guiotto,
Maria Sole Notari,
Diletta Morelli Venturi,
Alberto Ricchebuono,
Melissa Castagnoli,
Christoph Meier,
Francesca Nardelli,
Lucia Calucci,
Matteo Signorile,
Marco Taddei,
Valentina Crocellà,
Ferdinando Costantino
- We report the synthesis of Al-TFS, a novel aluminum metal-organic framework (MOF) based on tetrafluorosuccinic acid (H₂TFS), of formula Al(OH)(TFS)·1.5H₂O, introducing a new member to the family of perfluorinated MOFs. The structure of the MOF, solved ab-initio from laboratory powder X-ray diffraction data, displays structural analogies with that of the commercially available Al-fumarate (Basolite A520). The structure is composed of 1D infinite OH-bridged Al octahedra chains connected by the dicarboxylic linkers, designing rhombic channels decorated by fluorine atoms. Upon water removal, the MOF undergoes a phase transition leading to a moderate expansion of the unit cell. Volumetric analysis revealed the presence of ultra-micropores with a size lower than 4 Å. Gas sorption measurements demonstrated for Al-TFS a slightly higher CO₂ selectivity compared to N₂ and CH₄ than the Al-fumarate analogue, with peculiar shapes of the isotherms suggesting a dynamic response of the framework ...
Latest version: v1
Publication date: May 21, 2025
Moloud Kaviani,
Chiara Ricca,
Ulrich Aschauer
- Super-exchange most often leads to antiferromagnetism in transition-metal perovskite oxides, yet ferromagnetism or ferrimagnetism would be preferred for many applications, for example in data storage. While alloying, epitaxial strain and defects were shown to lead to ferromagnetism, engineering this magnetic order remains a challenge. We propose, based on density functional theory calculations, a novel route to defect-engineer ferrimagnetism, which is based on preferential displacements of oxygen vacancies due to finite temperature vibrations. This mechanism has an unusual temperature dependence, as it is absent at 0K, strengthens with increasing temperature before vanishing once oxygen vacancies disorder, giving it a unique experimentally detectable signature.
Latest version: v2
Publication date: May 20, 2025
Letizia Tavagnacco,
Sara Del Galdo,
Andrea Galli,
Barbara Capone,
Emanuela Zaccarelli,
Ester Chiessi
- The thermoresponsiveness of polymer-based soft materials opens perspectives in many applicative fields. This property in hydrated systems has the simple origin of a reversible de-mixing across a lower critical solution temperature, and has been explored for several chemically different amphiphilic polymers, each of them with specific critical conditions and phase behaviours. This work investigates for the first time by extensive atomistic molecular dynamics simulations the temperature dependence of the infinitely diluted aqueous solution of two such thermoresponsive macromolecules, poly(N-isopropyl-methacrylamide), PNIPMAM, and poly(2-isopropyl-2-oxazoline), PIPOX, in comparison to poly(N-isopropylacrylamide), PNIPAM, the much-more studied prototype system for polymers exhibiting a lower consolute boundary in water. The evolution of conformation and hydration water of the macromolecules is detected in a temperature range from well-below to well-above the transition temperature, ...
Latest version: v1
Publication date: May 19, 2025
Michelangelo Domina,
Filippo Bigi,
Paolo Pegolo,
Michele Ceriotti
- Rotational symmetry plays a central role in physics, providing an elegant framework to describe how the properties of 3D objects – from atoms to the macroscopic scale – transform under the action of rigid rotations. Equivariant models of 3D point clouds are able to approximate structure-property relations in a way that is fully consistent with the structure of the rotation group, by combining intermediate representations that are themselves spherical tensors. The symmetry constraints however make this approach computationally demanding and cumbersome to implement, which motivates increasingly popular unconstrained architectures that learn approximate symmetries as part of the training process.
In this work, we explore a third route to tackle this learning problem, where equivariant functions are expressed as the product of a scalar function of the point cloud coordinates and a small basis of tensors with the appropriate symmetry. We also propose approximations of the general ...
Latest version: v1
Publication date: May 09, 2025
Daria Torodii,
Manuel Cordova,
Jacob Holmes,
Pinelopi Moutzouri,
Tommaso Casalini,
Sten Nilsson Lill,
Arthur Pinon,
Christopher Knee,
Anna Svensk Ankarberg,
Okky Dwichandra Putra,
Staffan Schantz,
Lyndon Emsley
- Amorphous formulations are increasingly used in the pharmaceutical industry due to their increased solubility, but their structural characterization at atomic-level resolution remains extremely challenging. Here, we characterize the complete atomic-level structure of an amorphous glucagon-like peptide-1 receptor (GLP-1R) agonist using chemical shift driven NMR crystallography. The structure is determined from measured chemical shift distributions for 17 of the 32 carbon atoms and 16 of the 31 hydrogen atoms in the molecule. The chemical shifts are able to provide a detailed picture of the atomic-level conformations and interactions, and we identify the structural motifs that play a major role in stabilization of the amorphous form. In particular, hydrogen bonding of the carboxylic acid proton is strongly promoted although no carboxylic acid dimer is formed. Two orientations of the benzodioxole ring are promoted in the NMR structure, corresponding to a significant stabilization ...
Latest version: v1
Publication date: May 08, 2025
Yao Luo,
Jinsoo Park,
Marco Bernardi
- Summing all Feynman diagrams with quantitative accuracy is a holy grail in theoretical physics. In condensed matter, the lattice vibration (phonon) field couples with the electrons, leading to the formation of entangled electron-phonon (e-ph) states called polarons. In the intermediate- and strong-coupling regimes common to many conventional and quantum materials, a many-body treatment of polarons requires adding up a large number of e-ph diagrams. Diagrammatic Monte Carlo (DMC) is an efficient method for diagram summation and has been employed to study polarons within simplified e-ph models (Holstein, Frohlich, etc.). Here we show DMC calculations based on accurate first-principles e-ph interactions, enabling numerically exact results for ground-state and dynamical properties of polarons in real materials, including the polaron formation energy, effective mass, spectral weight, phonon cloud distribution, optical conductivity, and mobility. We demonstrate such DMC calculations ...
Latest version: v2
Publication date: May 08, 2025
Nelly Natsch,
Tara Tošić,
Jian-Rui Soh,
Nicola Spaldin
- We use spin dynamics simulations to determine the origin of the unusual correlated diffuse scattering, characterised by half-moon shapes bridging the magnetic Bragg peaks, observed in the polarised elastic neutron scattering from manganese tungstate, MnWO₄. We first fit a Heisenberg Hamiltonian with twelve nearest-neighbour exchange interactions and single-ion anisotropy to the experimental ground-state magnon dispersion. We then show via spin dynamics simulations that our model Hamiltonian both reproduces the experimentally observed half-moon features and captures their persistence into the paramagnetic regime. Moreover, we identify the three-dimensional, competing antiferromagnetic interactions driving this behavior. Our work complements earlier studies of half-moon-shaped signatures in pyrochlore and triangular structures, by providing insight into their origin in a zigzag chain geometry with three-dimensional competing exchange interactions.
Latest version: v1
Publication date: May 07, 2025
Zhe Liu,
Shashi Mishra,
Jae-Mo Lihm,
Samuel Poncé,
Elena Margine
- Topological Weyl semimetals represent a novel class of quantum materials that exhibit remarkable properties arising from their unique electronic structure. In this work, we employ state-of-the-art ab initio methods to investigate the role of the electron-phonon interactions on the charge transport properties of TaAs. Our calculations of the temperature-dependent electrical conductivity with the iterative Boltzmann transport equation show excellent agreement with experimental measurements above 100 K. Extending the analysis to doped systems, we demonstrate that even small shifts in the Fermi level can lead to substantial changes in conductivity, driven by the complex topology of the Fermi surface. In particular, modifications in Fermi surface nesting emerge as a key factor influencing scattering processes and carrier lifetimes. These findings offer critical insights into the microscopic mechanisms that govern transport in TaAs and highlight the sensitivity of Weyl semimetals to ...
Latest version: v1
Publication date: May 05, 2025
Colin Bundschu
- Earth-abundant spinel oxides are promising alkaline oxygen-reduction catalysts, yet mechanistic models still invoke a vacuum-DFT associative *OOH/*OO route. Here we combine >80,000 fully solvated joint-DFT calculations to map oxygen-reduction energetics across 442 Al-, Co-, Cr-, Fe-, Ga-, Mn-, Ni- and Zn-containing spinels on the (100) and (111) facets. Associative intermediates are >0.5 eV less stable than *OH/H states, revealing a four-step dissociative cycle in which surface-hydrogen passivation shuttles protons. These results establish solvated high-throughput DFT as a predictive lens on the kinetic oxygen-reduction limit of spinel oxides.
Latest version: v1
Publication date: Apr 30, 2025
Lars Bilke,
Thomas Fischer,
Tobias Meisel,
Dmitri Naumov
- Reproducibility in running scientific simulations on high-performance computing (HPC) environments is a persistent challenge due to variations in software and hardware stacks. Differences in software versions or hardware-specific optimizations often lead to discrepancies in simulation outputs. While Linux containers are commonly used to standardize software environments, tools like Docker lack reproducibility in image creation, requiring archiving of binary image blobs for future use. This method turns containers into black boxes, preventing verification of how the contained software was built.
In the linked paper, we demonstrate how we use GNU Guix to create our software stack bit-by-bit reproducible from a source bootstrap. Our approach incorporates a portable OpenMPI implementation, optimized software builds, and deployment via Apptainer images across three HPC environments. We show that our reproducible software stack facilitates consistent multi-physics simulations and ...
Latest version: v2
Publication date: Apr 30, 2025
Fabrizio Cossu,
Dhani Nafday,
Krisztián Palotás,
Mehdi Biderang,
Heung-Sik Kim,
Alireza Akbari,
Igor Di Marco
- We employ ab-initio electronic-structure calculations to investigate the charge-density waves and periodic lattice distortions in bilayer 2H-NbSe₂. We demonstrate that the vertical stacking can give rise to a variety of patterns that may lower the symmetry of the charge-density waves exhibited separately by the two composing 1H-NbSe₂ monolayers. The general tendency to a spontaneous symmetry breaking observed in the ground state and the first excited states is shown to originate from a non-negligible interlayer coupling. Simulated images for scanning tunneling microscopy as well as geometric structure factors show signatures of the different stacking orders. This may not only be useful to reinterpret past experiments on surfaces and thin films, but it may also be exploited to devise ad hoc experiments for the investigation of the stacking order in 2H-NbSe₂. We anticipate that our analysis not only applies to the 2H-NbSe₂, but is also relevant for thin films and bulk, whose ...
Latest version: v1
Publication date: Apr 29, 2025
Khanh Dang,
Sumit Suresh,
Avanish Mishra,
Ian Chesser,
Nithin Matthew,
Edward Kober,
Saryu Fensin
- Dislocation-grain boundary play a major role in the strength and ductility of structural materials. An understanding of governing parameters such as grain boundary local atomic structures on the outcome of this interaction can accelerate new alloy design strategies that tailors materials’ microstructures. Previous studies have focused only on the subset of minimum-energy grain boundary structures. We present a comprehensive database of dislocation-grain boundary interaction for edge, screw, and 60o mixed dislocation with 587 < 110 > and < 112 > symmetric tilt grain boundary in FCC Cu consisting of 73 minimum-energy grain boundary structures and 514 metastable ones. The dataset contains the outcomes for 5234 unique interactions with a particular dislocation type, grain boundary structure, and applied shear stress.
Latest version: v3
Publication date: Apr 28, 2025
Jarek Dabrowski
- Determining the atomic structure of a surface is essential for reliable simulations and in-depth exploration of chemical and atomic-scale physical processes. Using Ge(110) c(8×10) as a case study, this work employs Density Functional Theory (DFT) calculations to examine the role of vibrational entropy in surface reconstruction stability. The Ge(110) c(8×10) unit cell consists of interstitial-based pentamers (Universal Building Block model, UBB) interspersed with regions appearing in STM images as unreconstructed. DFT calculations predict that adding more pentamers lowers the surface energy, contradicting experimental findings. This discrepancy is resolved when vibrational entropy is accounted for and sur-face divacancies are introduced in addition to the UBB pentamers. These divacancies are similar to those proposed earlier in the Tetramer-Heptagonal and Tetragonal Ring (THTR) reconstruction model. The nearest neighbors of the vacancy sites are rebonded as on monatomic step edges. ...
Latest version: v1
Publication date: Apr 23, 2025
Michelle Ernst,
Jürg Hutter,
Stefano Battaglia
- Covalent organic frameworks (COFs) are materials of growing interest for electronic applications due to their tunable structures, chemical stability, and layered architectures that support extended π-systems and directional charge transport. While their electronic properties are strongly influenced by the choice of molecular building blocks and the stacking arrangement, experimental control over these features remains limited, and the number of well-characterized COFs is still relatively small. Here, we explore two alternative strategies, hydrostatic pressure and metal intercalation, to tune the electronic structure of COFs. Using periodic density functional theory (DFT) calculations, we show that the band gap of pristine COF-1 decreases by ∼1 eV under compression up to 10 GPa. Metal intercalation induces an even greater reduction, in some cases leading to metallic behavior. We demonstrate that pressure and intercalation offer effective, continuous control over COF electronic ...
Latest version: v1
Publication date: Apr 22, 2025
Gabriel de Miranda Nascimento,
Flaviano José dos Santos,
Marnik Bercx,
Giovanni Pizzi,
Nicola Marzari
- A major challenge in first-principles high-throughput materials simulations is automating the selection of parameters used by simulation codes in a way that robustly ensures numerical precision and computational efficiency. Here, we propose a rigorous methodology to assess the quality of self-consistent DFT calculations with respect to smearing and k-point sampling across a wide range of crystalline materials. To achieve this, we develop criteria to reliably control average errors in total energies, forces, and other properties as a function of the desired computational efficiency, while consistently suppressing uncontrollable k-point sampling errors. Our results provide automated protocols for selecting optimized parameters based on different precision and efficiency tradeoffs. This archive contains all data related to the material structures and calculation workflows developed in this work.
Latest version: v2
Publication date: Apr 17, 2025
Laura Arango-Tabares,
Julian D. Correa,
Olga Lopez-Acevedo
- We performed a computational study using Density Functional Theory calculations on a copper-graphene system. A global minima search was performed using the Minima Hopping algorithm to find multiple graphene isomers that can appear on different substrates. As a model of copper substrate, we used a 112 copper atom cluster and as a model of graphene flake, we used 40 carbon atoms on top of the copper surface. The system was placed in vacuum to guarantee no interaction between images.
The dataset contains coordinates of graphene flake isomers on crystalline and amorphous Cu substrates.
Latest version: v1
Publication date: Apr 17, 2025
Kyung-Shik Kim*,
Qing-Jie Li*,
Ju Li,
Cemal Cem Tasan
- This archive includes the raw data for atomistic simulations in the work as titled. Transition to a hydrogen-based economy requires a thorough understanding of hydrogen interaction with dislocations in metals, especially in body-centered cubic (BCC) steels. Past experimental and computational investigations regarding these interactions often demonstrate two opposing results: hydrogen-induced mobility or hydrogen-induced pinning of dislocations. Through in-situ scanning electron microscopy experiments enabled by a custom-built setup, we address here this discrepancy. Our experiments reveal hydrogen-induced dislocation motion in a BCC metal at room temperature. Interestingly however, we also observe that the same dislocations are later pinned as well, again induced by the steady hydrogen flux. Molecular dynamics simulations of the phenomena confirm the attraction of the dislocations towards the hydrogen flux, and the pinning that follows after, upon increased hydrogen trapping at ...
Latest version: v1
Publication date: Apr 16, 2025
Alfredo Fiorentino,
Paolo Pegolo,
Stefano Baroni,
Davide Donadio
- Semiconducting alloys, in particular SiGe, have been employed for several decades as high- temperature thermoelectric materials. Devising strategies to reduce their thermal conductivity may provide a substantial improvement in their thermoelectric performance also at lower temper- atures. We have carried out an ab initio investigation of the thermal conductivity of SiGe alloys with random and spatially correlated compositional disorder employing the Quasi-Harmonic Green- Kubo (QHGK) theory with force constants computed from density functional theory. Leveraging QHGK and the hydrodynamic extrapolation to achieve size convergence, we obtained a detailed understanding of lattice heat conduction in SiGe and demonstrated that colored disorder suppresses thermal transport across the acoustic vibrational spectrum, leading to up to a 4-fold enhancement in the intrinsic thermoelectric figure of merit.
This record contains input and analysis scripts to reproduce the findings of this article.
Latest version: v1
Publication date: Apr 15, 2025
Ran Mo,
Zhishuo Huang,
Liviu Ungur
- Fullerides forms a big familiy of molecular crystals exhibiting various useful electro- and magnetochemical properties. Therefore, an efficient in silico method is desirable to look into such chemical system. To alleviate the burden of computationally-heavy first-principles calculations, here we present the successful attempts of using Machine Learning Force Field (MLFF) in predicting dynamical properties of the alkali-doped fulleride K₃C₆₀. Two on-the-fly Gaussian-Process-MLFF schemes based on different atomistic descriptors, Smooth Overlap of Atomic Position (SOAP) and Atomic Cluster Expansion (ACE), have been experimented. The performance of generated K₃C₆₀ MLFFs are validated by accurate prediction on energy and forces of 1,000 randomly disturbed K₃C₆₀ structures compared to respective DFT results. Several other dynamical properties including phonon dispersion, elastic moduli and heat capacity obtained by MLFFs have also shown good agreement with results from DFT calculations, ...
Latest version: v1
Publication date: Apr 11, 2025
Virginie de Mestral,
Lorenzo Bastonero,
Michele Kotiuga,
Marko Mladenovic,
Nicola Marzari,
Mathieu Luisier
- We present an ab initio method to calculate the clamped Pockels tensor of ferroelectric materials from density-functional theory (DFT), the modern theory of polarization exploiting the electric-enthalpy functional, and automated first- and second-order finite-difference derivatives of the polarizations and the Hellmann-Feynman forces. Thanks to the functional-independent capabilities of our approach, we can determine the Pockels tensor of tetragonal barium titanate (BTO) beyond the local density approximation (LDA), with arbitrary exchange-correlation (XC) functionals, for example, PBEsol. The latter, together with RRKJ ultra-soft pseudo-potentials (PP) and a supercell exhibiting local titanium off-centering, enables us to stabilize the negative optical phonon modes encountered in tetragonal BTO when LDA and norm-conserving PP are combined. As a result, the correct value range of r51, the largest experimental Pockels coefficient of BTO, is recovered. We also reveal that r51 ...
Latest version: v1
Publication date: Apr 11, 2025
Cécile Pot d'or,
Richard Chukwu,
Doriano Brogioli,
Fabio La Mantia
- We present a simulation of dynamic electrochemical impedance spectroscopy using numerical methods based on the finite element solution of differential equations. While the study of electrochemical systems during operation is of great interest, one is always confronted with challenges due to non-linearities when exciting the system with both a cyclic voltammetry and a multi-sine. We therefore propose a two-component-model, which first solves for the cyclic voltammetry and then calculates the effect of the multi-sine by means of linearization around the cyclic voltammetry of all the variables. We provide two models: (i) the dynamic transfer function model of DEIS during a redox reaction and (ii) a stationary version of model (i). Both models are based on an existing semi-analytical model described in reference #2.
Latest version: v1
Publication date: Apr 08, 2025
Edith Simmen,
Nicola A. Spaldin
- Using density-functional theory, we demonstrate that the formal layer charges of the metallic samarium nickelate electrode influence the spontaneous ferroelectric polarization of the barium titanate in SmNiO₃/BaTiO₃ capacitors. We find that, despite the metallic screening of SmNiO₃, the spontaneous polarization of BaTiO₃ always aligns with the layer polarization of the SmNiO₃ formal charges. We also find zero critical thickness for the ferroelectricity in BaTiO₃ in this orientation. The opposite polarization direction is highly disfavored for thin BaTiO₃ slabs but becomes less unstable with increasing slab thickness. We construct a simple electrostatic model that allows us both to study the behavior for thicker BaTiO₃ and SmNiO₃ slabs and to extract the influence of various material parameters on the behavior. We mimic a metal-insulator transition in the SmNiO₃ by varying the metallic screening length, which we find influences the stability of the ferroelectric polarization. Our ...
Latest version: v1
Publication date: Apr 07, 2025
Yang Hu,
Amit Sharma,
Aleksandr Druzhinin,
Claudia Cancellieri,
Vladyslav Turlo
- This study introduces new models that incorporate layer corrugation and interface roughness into standard approaches for measuring interface stress in nanomultilayers (NMLs). Applied to Cu/W NMLs, these models show that ignoring such features can inflate measured interface stress by up to 0.4 J/m^2. However, corrugation and roughness alone cannot account for the extreme stresses reported, suggesting that atomic-scale phenomena (e.g., intermixing and metastable phase formation at the interfaces) dominate. These findings highlight the importance of balancing bilayer counts and thickness-to-roughness ratios for reliable stress quantification, providing a practical pathway to designing and characterizing advanced nanocomposite coatings with improved accuracy.
Latest version: v1
Publication date: Apr 07, 2025
Ibrahim Buba Garba,
Lorenzo Trombini,
Claudine Katan,
Jacky Even,
Marios Zacharias,
Mikael Kepenekian,
George Volonakis
- This study employed density functional theory with doubly screened dielectric-dependent hybrid (DSH) functional to predict the band gaps of Pb- and Sn-based inorganic and hybrid 3D halide perovskites, as well as layered hybrid perovskites. The DSH functional employs material-dependent mixing parameters derived from macroscopic electronic dielectric constant, and accurately predicts band gaps for 3D perovskites only if structural local disorder is taken into account. For layered hybrid perovskites, we propose using the calculated dielectric constant of the respective 3D perovskites to define the DSH screening. This dataset contains input and output files of all DFT and DSH calculations applied to Pb- and Sn-based layered halide perovskites with various organic spacers and multilayered structures, such as BA series with n =1, 2, 3. The computational framework introduced here provides an efficient parameter-free ab initio methodology suitable for predicting the electronic properties ...
Latest version: v1
Publication date: Apr 02, 2025
In Won Yeu,
Annika Stuke,
Alexander Urban,
Nongnuch Artrith
- This database contains the reference data used for direct force training of Artificial Neural Network (ANN) interatomic potentials using the atomic energy network (ænet) and ænet-PyTorch packages (https://github.com/atomisticnet/aenet-PyTorch). It also includes the GPR-augmented data used for indirect force training via Gaussian Process Regression (GPR) surrogate models using the ænet-GPR package (https://github.com/atomisticnet/aenet-gpr).
Each data file contains atomic structures, energies, and atomic forces in XCrySDen Structure Format (XSF). The dataset includes all reference training/test data and corresponding GPR-augmented data used in the four benchmark examples presented in the reference paper, “Scalable Training of Neural Network Potentials for Complex Interfaces Through Data Augmentation”.
A hierarchy of the dataset is described in the README.txt file, and an overview of the dataset is also summarized in supplementary Table S1 of the reference paper.
Latest version: v1
Publication date: Apr 02, 2025
Quentin Bizot,
Noel Jakse
- Solidification control is crucial in manufacturing technologies, as it determines the microstructureand, consequently, the performance of the final product. Investigating the mechanisms occurring during the early stages of nucleation remains experimentally challenging as it initiates on nanometer length and sub-picoseconds time scales. Large scale molecular dynamics simulations using machinelearning interatomic potential with quantum accuracy appears the dedicated approach to complex,atomic level, multidimensional mechanisms with local symmetry breaking. A potential trained ona high-dimensional neural network on density functional theory-based ab initio molecular dynamics(AIMD) trajectories for liquid and undercooled states for Al-Si binary alloys enables us to study the nucleation mechanisms occurring at the early stages from the liquid phase near the eutectic composition. Our results indicate that nucleation starts with Al at hypoeutectic compositions and ...
Latest version: v1
Publication date: Apr 02, 2025
Roberta Favata,
Nicolas Baù,
Antimo Marrazzo
- Two-dimensional topological insulators are characterized by an insulating bulk and conductive edge states protected by the nontrivial topology of the bulk electronic structure. They remain robust against moderate disorder until Anderson localization occurs and destroys the topological phase. Interestingly, disorder can also induce a topological phase—known as a topological Anderson insulator—starting from an otherwise pristine trivial phase. While topological invariants are generally regarded as global quantities, we argue that space-resolved topological markers can act as local order parameters, revealing the role of fluctuations and correlations in the local topology under Anderson disorder and vacancies. With this perspective, we perform numerical simulations of disorder-driven topological phase transitions in the Haldane and Kane-Mele models, using supercells with both open and periodic boundary conditions. We find that short-scale fluctuations of topological markers vanish ...
Latest version: v1
Publication date: Mar 31, 2025
Zihan Lin,
Dong Chen,
Wenlong Lu,
Xin Liang,
Shiyu Feng,
Kohei Yamagami,
Jacek Osiecki,
Mats Leandersson,
Balasubramanian Thiagarajan,
Junwei Liu,
Claudia Felser,
Junzhang Ma
- Altermagnetism exhibits unique physical properties such as spin-momentum locking, anomalous Hall effect, nontrivial topological phase, and giant magnetoresistance. Among all the predicted candidates, several room temperature altermagnets are suggested to host significant potential applications. RuO₂ has been proposed as the most promising candidate. However, recently, there is intense debate about whether RuO₂ exhibits magnetic order or not. Experiments by several different technologies claim the collinear magnetic order and spin splitting induced effects. However, very recent μSR results reveal no magnetic order in RuO₂ which indicates that the time reversal symmetry is not broken. Direct observation of the high-resolution bulk band structure is absent up to date, but essential to investigate the electronic structure of RuO₂. In this study, utilizing soft X-ray ARPES, we report systematic direct experimental observation of bulk band structure of RuO₂. We observed signature of ...
Latest version: v1
Publication date: Mar 28, 2025
Luca Bellucci,
Valentina Tozzini,
Zacharias Fthenakis,
Mauro Francesco Sgroi,
Francesco Delfino
- A database of 600 atomistic models of reduced graphene oxide (rGO) and hydrogenated rGO (H-rGO) was constructed, comprising 120 rGO and 480 H-rGO structures. The dataset spans a broad range of oxygen concentrations, –O–:–OH (epoxy/ether to hydroxyl) ratios, and hydrogenation levels. The database is designed for applications in computational modeling, machine learning, and structure–property analyses. The models were generated following a three-step simulation protocol:
– Step 1 | Generation of Pseudo-GO Models: Graphene sheets were functionalized with oxygen groups (–O– or –OH), randomly distributed according to three –O–:–OH ratios (25:75, 50:50, and 75:25). Functionalization was applied symmetrically on both sides of the sheet, avoiding adjacent carbon atoms.
– Step 2 | Thermal Reduction: Each pseudo-GO structure was subjected to annealing at four different temperatures (1000, 1500, 2000, and 2500 K). After initial relaxation at 300 K, the models were heated, equilibrated, ...
Latest version: v1
Publication date: Mar 27, 2025
Félix Antoine Goudreault,
Samuel Poncé,
Feliciano Giustino,
Michel Côté
- Using density functional theory calculations with spin-orbit coupling (SOC), we report on the temperature-dependent thermodynamical properties of Pb: electrical resistivity, thermal expansion (TE), heat capacity, bulk modulus and its pressure derivative. For the former, we employed the state-of-the-art ab initio Boltzmann Transport Equation formalism, and we calculated the effect of TE. In accordance with previous work, we show that SOC improves the description of the phonon dispersion and the resistivity. We argue that this is caused by a joint mutual effect of an increase in the electronic nesting and an increase in the electron-phonon coupling. Interestingly, including TE incorporates non-linearity into the resistivity at high temperatures, whose magnitude depends on whether SOC is included or not. We suggest that mechanisms beyond the quasi-harmonic approximation should be considered to get a better description of Pb with SOC at high temperatures.
Latest version: v1
Publication date: Mar 20, 2025
Jae-Mo Lihm,
Samuel Poncé
- This file contains all the data, as well as the code necessary to reproduce the results of Jae-Mo Lihm and Samuel Ponce, "Non-perturbative self-consistent electron-phonon spectral functions and transport." Electron-phonon coupling often dominates the electron spectral functions and transport properties. However, studies of this effect in real materials have largely relied on perturbative one-shot methods due to the lack of a first-principles theoretical and computational framework. Here, we present a self-consistent theory and implementation for the non-perturbative calculations of spectral functions and conductivity due to electron-phonon coupling. Applying this method to monolayer InSe, we demonstrate that self-consistency qualitatively affects the spectral function and transport properties compared to state-of-the-art one-shot calculations and allow one to reconcile experimental angle-resolved photoemission experiments. The developed method can be widely applied to materials ...
Latest version: v1
Publication date: Mar 19, 2025
Nina Girotto Erhardt,
Jan Berges,
Samuel Poncé,
Dino Novko
- We investigate the superconducting properties of molybdenum disulphide (MoS₂) monolayer across a broad doping range, successfully recreating the so far unresolved superconducting dome. Our first-principles findings reveal several dynamically stable phases across the doping-dependent phase diagram. We observe a doping-induced increase in the superconducting transition temperature Tc, followed by a reduction in Tc due to the formation of charge density waves (CDWs), polaronic distortions, and structural transition from the H to the 1T′ phase. Our work reconciles various experimental observations of CDWs in MoS₂ with its doping-dependent superconducting dome structure, which occurs due to the 1×1 H to 2×2 CDW phase transition.
Latest version: v1
Publication date: Mar 19, 2025
Gianrico Lamura,
Daniel Tay,
Roustem Khassanov,
Paola Gentile,
Chunqiang Xu,
Xianglin Ke,
Ifeanyi John Onuorah,
Pietro Bonfà,
Xiaofeng Xu,
Toni Shiroka
- The intermetallic quasi-one-dimensional binary superconductor V2Ga5 was recently found to exhibit a topologically nontrivial normal state, making it a natural candidate for a topological superconductor.
By combining dc-magnetization, nuclear magnetic resonance, and muon-spin rotation (µSR) measurements on high-quality V2Ga5 single crystals, we investigate the electronic properties of its normal- and superconducting ground states. NMR measurements in the normal state indicate a strong anisotropy in both the line shifts and the relaxation rates. Such anisotropy persists also in the superconducting state, as shown by the magnetization and µSR-spectroscopy results. In the latter case, data collected at different temperatures, pressures, and directions of the magnetic field (with respect to the crystalline axes) evidence a fully-gapped, strongly anisotropic superconductivity. At the same time, hydrostatic pressure is shown to only lower the ...
Latest version: v1
Publication date: Mar 19, 2025
Benjamin Chang,
Iurii Timrov,
Jinsoo Park,
Jin-Jian Zhou,
Nicola Marzari,
Marco Bernardi
- Understanding electronic interactions in high-temperature superconductors is an outstanding challenge. In the widely studied cuprate materials, experimental evidence points to strong electron-phonon (e-ph) coupling and broad photoemission spectra. Yet, the microscopic origin of this behavior is not fully understood. Here we study e-ph interactions and polarons in a prototypical parent (undoped) cuprate, La₂CuO₄ (LCO), by means of first-principles calculations. Leveraging parameter-free Hubbard-corrected density functional theory, we obtain a ground state with band gap and Cu magnetic moment in nearly exact agreement with experiments. This enables a quantitative characterization of e-ph interactions. Our calculations reveal two classes of longitudinal optical (LO) phonons with strong e-ph coupling to hole states. These modes consist of Cu-O plane bond-stretching and bond-bending as well as vibrations of apical O atoms. The hole spectral functions, obtained with a cumulant method ...
Latest version: v1
Publication date: Mar 17, 2025
Luca Binci,
Nicola Marzari,
Iurii Timrov
- Spin excitations play a fundamental role in understanding magnetic properties of materials, and have significant technological implications for magnonic devices. However, accurately modeling these in transition-metal and rare-earth compounds remains a formidable challenge. Here, we present a fully first-principles approach for calculating spin-wave spectra based on time-dependent (TD) density-functional perturbation theory (DFPT), using nonempirical Hubbard functionals. This approach is implemented in a general noncollinear formulation, enabling the study of magnons in both collinear and noncollinear magnetic systems. Unlike methods that rely on empirical Hubbard U parameters to describe the ground state, and Heisenberg Hamiltonians for describing magnetic excitations, the methodology developed here probes directly the dynamical spin susceptibility (efficiently evaluated with TDDFPT throught the Liouville-Lanczos approach), and treats the linear variation of the Hubbard ...
Latest version: v1
Publication date: Mar 17, 2025
Jinzhen Huang,
Adam H. Clark,
Natasha Hales,
Kenneth Crossley,
Julie Guehl,
Radim Skoupy,
Thomas J. Schmidt,
Emiliana Fabbri
- Transition metal oxides (e.g., cobalt oxides) often undergo a dynamic surface reconstruction under oxygen evolution reaction (OER) conditions to form the active state, which differs in response to the electrolyte pH. The resulting pH-dependency of OER activity is commonly observed but poorly understood. Herein, we demonstrate that operando X-ray absorption spectroscopy (XAS) characterization enables tracking of the Co oxidation transformation at different pH-directed (hydr)oxide/electrolyte interfaces. Combined with in situ electrochemical analyses, correlations between Co redox dynamics, flat band potential and Co oxidation transformations are established to explain the pH-dependency of OER activity. In alkaline environments, the low flat band potential allows a low-potential Co redox transformation, which in turns favors surface reconstruction. In neutral and acidic environments, an anodic shift of the Co redox transformation increases the OER overpotential, particularly in an ...
Latest version: v1
Publication date: Mar 17, 2025
Marnik Bercx,
Samuel Poncé,
Yiming Zhang,
Giovanni Trezza,
Amir Ghorbani Ghezeljehmeidan,
Lorenzo Bastonero,
Junfeng Qiao,
Fabian O. von Rohr,
Giovanni Pizzi,
Eliodoro Chiavazzo,
Nicola Marzari
- We perform a high-throughput computational search for novel phonon-mediated superconductors, starting from the Materials Cloud 3-dimensional database (MC3D) of experimentally known inorganic stoichiometric compounds. We first compute the Allen-Dynes critical temperature Tc for 4533 non-magnetic metals using a direct and progressively finer sampling of the electron-phonon couplings. For the candidates with the largest Tc, we use automated Wannierizations and electron-phonon interpolations to obtain a high-quality dataset for the most promising 240 dynamically stable structures, for which we calculate spectral functions, superconducting bandgaps, and isotropic Migdal-Eliashberg critical temperatures. For 110 of these, we also provide anisotropic Migdal-Eliashberg superconducting gaps and critical temperatures. The approach is remarkably successful in finding known superconductors, and we find 24 unknown ones with a predicted anisotropic Tc above 10 K. Among them, we identify a ...
Latest version: v1
Publication date: Mar 13, 2025
Julia Linke,
Thomas Rohrbach,
Adam Hugh Clark,
Michal Andrzejewski,
Nicola Pietro Maria Casati,
Fabian Luca Buchauer,
Mikkel Rykær Kraglund,
Christodoulos Chatzichristodoulou,
Eibhlin Meade,
Marco Ranocchiari,
Thomas Justus Schmidt,
Emiliana Fabbri
- Metal-organic frameworks (MOFs) as electrocatalysts for the alkaline oxygen evolution reaction (OER) show promising catalytic activity by offering great variability and high surface areas, enabling performance optimization and mechanistic studies. However, their stability during reaction and the structure-performance relationship defining the origin of the high OER activity, are still vigorously debated. Herein, we leverage operando X-ray absorption spectroscopy and operando X-ray diffraction to unveil the structural and electronic transformations of Ni-MOF-74 during OER. We identify the irreversible destruction of the MOF-74 crystal into a highly OER active, amorphous NiOOH-metal organic compound. Based on these findings, we propose an amorphous Ni metal organic compound (Ni-MOC*) for achieving high current densities both in a three-electrode cell (14 A gNi-1 at 1.5 VRHE) and in an anion exchange membrane water electrolyzer (AEM-WE) with a stable AEM-WE performance exceeding 100 h at 500 mA cm-2.
Latest version: v1
Publication date: Mar 12, 2025
Chuntian Cao,
Chunyi Zhang,
Xifan Wu,
Matthew R. Carbone,
Hubertus van Dam,
Shinjae Yoo,
Deyu Lu
- This database contains the neural network potential (NNP) model and training data for aqueous ZnCl₂ solutions from 1 m to 30 m. The NNP model can be used to compute total energies and atomic forces, with one of its major applications being large-scale molecular dynamics (MD) simulations. The model was trained using DeePMD-kit v2.2.1, with training data generated through an active learning approach implemented in DP-GEN. The energies and forces in the training set were obtained from density functional theory (DFT) calculations using the SCAN exchange-correlation functional performed using Quantum ESPRESSO. Further details on the ab initio calculation procedures and model training methodology are available in the associated manuscript (see reference below).
Latest version: v1
Publication date: Mar 11, 2025
Ewelina Pabiś-Mazgaj,
Tomasz Gawenda,
Agata Stempkowska
- This study proposes an eco-friendly approach to zeolite agglomeration for petroleum sorbents. The novelty lies in integrating agglomeration and deagglomeration within a single high-pressure grinding roll (HPGR) system, enhancing sorption capacity by creating a secondary porosity network. This eliminates energy-intensive calcination, making it a sustainable alternative to wet granulation. We examine the impact of binder and water dosages on sorption capacity, mechanical resistance, and textural properties of roll-compacted zeolite agglomerates. Feed materials were characterized using N₂ adsorption, XRD, XRF, particle size distribution, and SEM. Structural and functional properties were assessed via mercury intrusion porosimetry, petroleum sorption efficiency (Westinghouse test), sorption capacity, gravitational drop tests, and SEM. All sorbents (0.5–1 mm) met the 50 wt.% oil absorbency threshold for petroleum spill cleanup in Poland. The fabricated zeolite agglomerates exhibited ...
Latest version: v1
Publication date: Mar 10, 2025
Yang Hu,
Vladyslav Turlo
- Experiments reveal negative (non-Laplacian) surface stresses in metal oxide nanoparticles, partly associated with humidity during fabrication and annealing. Using a neural network interatomic potential for MgO, we prove that water adsorption induces surface hydroxylation, shifting facets from {100} to {110} to {111} and switching the average surface stress from positive to negative. Predicted lattice strains versus nanoparticle size agree well with experiments, clarifying experimental correlations. The new framework informs broad applications in catalysis, sensors, batteries, and biomedicine.
Latest version: v1
Publication date: Mar 07, 2025
Yann Lorris Müller,
Anirudh Raju Natarajan
- Cluster expansions are commonly employed as surrogate models to link the electronic structure of an alloy to its finite-temperature properties. Using cluster expansions to model materials with several alloying elements is challenging due to a rapid increase in the number of fitting parameters and training set size. We introduce the embedded cluster expansion (eCE) formalism that enables the parameterization of accurate on-lattice surrogate models for alloys containing several chemical species. The eCE model simultaneously learns a low dimensional embedding of site basis functions along with the weights of an energy model. A prototypical senary alloy comprised of elements in groups 5 and 6 of the periodic table is used to demonstrate that eCE models can accurately reproduce ordering energetics of complex alloys without a significant increase in model complexity. Further, eCE models can leverage similarities between chemical elements to efficiently extrapolate into compositional ...
Latest version: v1
Publication date: Feb 27, 2025
Lorenzo Bastonero,
Cristiano Malica,
Eric Macke,
Marnik Bercx,
Sebastian P. Huber,
Iurii Timrov,
Nicola Marzari
- We introduce an automated, flexible framework (aiida-hubbard) to self-consistently calculate Hubbard U and V parameters from first-principles. By leveraging density-functional perturbation theory, the computation of the Hubbard parameters is efficiently parallelized using multiple concurrent and inexpensive primitive cell calculations. Furthermore, the intersite V parameters are defined on-the-fly during the iterative procedure to account for atomic relaxations and diverse coordination environments. We devise a novel, code-agnostic data structure to store Hubbard related information together with the atomistic structure, to enhance the reproducibility of Hubbard-corrected calculations. We demonstrate the scalability and reliability of the framework by computing in high-throughput fashion the self-consistent onsite U and intersite V parameters for 115 Li-containing bulk solids with up to 32 atoms in the unit cell. Our analysis of the Hubbard parameters calculated reveals a ...
Latest version: v1
Publication date: Feb 27, 2025
Yuqing He,
Pierre-Paul De Breuck,
Hongming Weng,
Matteo Giantomassi,
Gian-Marco Rignanese
- A dataset of 35,608 materials with their topological properties is constructed by combining the density functional theory (DFT) results of Materiae and the Topological Materials Database. Thanks to this, machine-learning approaches are developed to categorize materials into five distinct topological types, with the XGBoost model achieving an impressive 85.2% classification accuracy. By conducting generalization tests on different sub-datasets, differences are identified between the original datasets in terms of topological types, chemical elements, unknown magnetic compounds, and feature space coverage. Their impact on model performance is analyzed.
Turning to the simpler binary classification between trivial insulators and nontrivial topological materials, three different approaches are also tested. Key characteristics influencing material topology are identified, with the maximum packing efficiency and the fraction of p valence electrons being highlighted as critical features.
Latest version: v2
Publication date: Feb 26, 2025
Alberto Carta,
Iurii Timrov,
Peter Mlkvik,
Alexander Hampel,
Claude Ederer
- Several methods have been developed to improve the predictions of density functional theory (DFT) in the case of strongly correlated electron systems. Out of these approaches, DFT+U, which corresponds to a static treatment of the local interaction, and DFT combined with dynamical mean field theory (DFT+DMFT), which considers local fluctuations, have both proven incredibly valuable in tackling the description of materials with strong local electron-electron interactions. While it is in principle known that the Hartree-Fock (HF) limit of the DFT+DMFT approach should recover DFT+U, demonstrating this equivalence in practice is challenging, due to the very different ways in which the two approaches are generally implemented. In this work, we introduce a way to perform DFT+U calculations in QE using Wannier functions as calculated by Wannier90, which allows us to use the same Hubbard projector functions both in DFT+U and in DFT+DMFT. We benchmark these DFT+U calculations against ...
Latest version: v1
Publication date: Feb 26, 2025
Isshu Lee,
John W. Merickel,
Yugandhar Kasala Sreenivasulu,
Fei Xu,
Yalei Tang,
Joshua E. Rittenhouse,
Aleksandar Vakanski,
Rongjie Song
- The dataset contains records of Charpy V-notch impact tests of nuclear structural materials. The focus is on studying the influence of specimen dimensions and geometry on Charpy impact test properties. The dataset was created through an extensive literature review of scientific articles. The extracted data points from the literature review are organized into a tabular format database containing 4,961 test records with 55 parameters, including material type and composition, manufacturing information, irradiation conditions, specimen size and dimensions, and Charpy properties. Materials science experts conducted systematic validation checks to ensure the accuracy of the information related to material type, manufacturing processes, treatment methods, chemical composition, testing conditions, as well as other pertinent information.
Latest version: v1
Publication date: Feb 26, 2025
Ardalan Hayatifar,
Simon Gravelle,
Beatriz D. Moreno,
Valerie A. Schoepfer,
Matthew B. J. Lindsay
- Interfacial processes involving metal (oxyhydr)oxide phases are important for the mobility and bioavailability of nutrients and contaminants in soils, sediments, and water. Consequently, these processes influence ecosystem health and functioning, and have shaped the biological and environmental co-evolution of Earth over geologic time. Here we employ reactive molecular dynamics simulations, supported by synchrotron X-ray spectroscopy to study the molecular-scale interfacial processes that influence surface complexation in ferrihydrite-water systems containing aqueous molybdate. We validate the utility of this approach by calculating surface complexation models directly from simulations. The reactive force-field captures the realistic dynamics of surface restructuring, surface charge equilibration, and the evolution of the interfacial water hydrogen bond network in response to adsorption and proton transfer. We find that upon hydration and adsorption, ferrihydrite restructures into ...
Latest version: v1
Publication date: Feb 19, 2025
Felippe Colombari,
Asdrubal Lozada-Blanco,
Weverson Gomes,
Jessica Ma,
Nicholas Kotov,
André de Moura
- We survey the different definitions of chirality and the methods that have been devised to compute chirality metrics, with emphasis on the methods that became prevalent in chemistry and materials science, the Hausdorff Chirality Measure (HCM) and the Osipov-Pickup-Dunmur (OPD) index. We also discuss the recently introduced Graph Theoretical Chirality (GTC) index, which is expected to become an alternative to the OPD index. We demonstrate how these different approaches can be applied to systems ranging from a few nanometers to micrometers and above, as long as structural information is available from either computer simulations or experimental data. These recent breakthroughs in the calculation of chirality metrics should pave the way to deepen our understanding of how primary chiral information is translated into secondary chiral properties and how these lead to applications, providing the basis for a theory of chiral nanomaterials.
Latest version: v1
Publication date: Feb 19, 2025
Martin Uhrin,
Austin Zadoks,
Luca Binci,
Nicola Marzari,
Iurii Timrov
- Density-functional theory with extended Hubbard functionals (DFT+U+V) provides a robust framework to accurately describe complex materials containing transition-metal or rare-earth elements. It does so by mitigating self-interaction errors inherent to semi-local functionals which are particularly pronounced in systems with partially-filled d and f electronic states. However, achieving accuracy in this approach hinges upon the accurate determination of the on-site U and inter-site V Hubbard parameters. In practice, these are obtained either by semi-empirical tuning, requiring prior knowledge, or, more correctly, by using predictive but expensive first-principles calculations. This archive entry contains Hubbard parameters, occupation matrices and other data calculated for 28 materials and covers all steps in a self-consistent procedure where, at each step new Hubbard parameters are obtained via linear-response, a process that is repeated until the parameters no longer change. The ...
Latest version: v2
Publication date: Feb 05, 2025
Lucas Clarte,
Adrien Vandenbroucque,
Guillaume Dalle,
Bruno Loureiro,
Florent Krzakala,
Lenka Zdeborova
- We investigate popular resampling methods for estimating the uncertainty of statistical models, such as subsampling, bootstrap and the jackknife, and their performance in high-dimensional supervised regression tasks. We provide a tight asymptotic description of the biases and variances estimated by these methods in the context of generalized linear models, such as ridge and logistic regression, taking the limit where the number of samples n and dimension d of the covariates grow at a comparable fixed rate α = n/d. Our findings are three-fold: i) resampling methods are fraught with problems in high dimensions and exhibit the double-descent-like behavior typical of these situations; ii) only when α is large enough do they provide consistent and reliable error estimations (we give convergence rates); iii) in the over-parametrized regime α < 1 relevant to modern machine learning practice, their predictions are not consistent, even with optimal regularization.
This record provides the ...
Latest version: v1
Publication date: Jan 30, 2025
Mahasweta Bagchi,
Philipp Rüßmann,
Gustav Bihlmayer,
Stefan Blügel,
Yoichi Ando,
Jens Brede
- Among the family of topological superconductors derived from Bi2Se3, Cux(PbSe)5(Bi2Se3)6 is unique in its surface termination of a single quintuple layer (QL) of the topological insulator (TI) Bi2Se3 on an ordinary insulator PbSe. Here, we report a combined scanning tunneling microscopy (STM) and density functional theory (DFT) characterization of the cleaved surface of the parent compound (PbSe)5(Bi2Se3)6 (PSBS). Interestingly, the potential disorder due to the random distribution of native defects is only Γ ∼ 4 meV, among the smallest reported for TIs. Performing high-resolution quasiparticle interference imaging (QPI) near the Fermi energy (E−EF = −1 eV to 0.6 eV) we reconstruct the dispersion relation of the dominant spectral feature and our ab initio calculations show that this surface feature originates from two bands with ...
Latest version: v1
Publication date: Jan 30, 2025
Jinzhen Huang,
Erica D. Clinton,
Kenneth Crossley,
Juliana Bruneli Falqueto,
Thomas J. Schmidt,
Emiliana Fabbri
- Electrochemical impedance spectroscopy (EIS) is the widely used technique to monitor the electrical properties of a catalyst under electrocatalytic conditions. Although it is extensively used for research in electrocatalysis, its effectiveness and power have not been fully harnessed to elucidate complex interfacial processes. Herein, we use the frequency dispersion parameter, n, which is extracted from EIS measurements, to describe the dispersion characteristics of capacitance and interfacial properties of Co3O4 under alkaline oxygen evolution reaction (OER) conditions. We first prove the n-value is sensitive to the interfacial electronic changes associated with Co redox processes and surface reconstruction. The n-value decreases by increasing the specific/active surface area of the catalysts. We further modify the interfacial properties by changing different components, i.e., replacing the proton with deuterium, adding ethanol as a new oxidant, and changing the cation in the ...
Latest version: v1
Publication date: Jan 28, 2025
Jacob Holmes,
Daria Torodii,
Martins Balodis,
Manuel Cordova,
Albert Hofstetter,
Federico Paruzzo,
Sten Nilsson Lill,
Emma Eriksson,
Pierrick Berruyer,
Bruno Simões de Almeida,
Mike Quayle,
Stefan Norberg,
Anna Svensk Ankarberg,
Staffan Schantz,
Lyndon Emsley
- We determine the complete atomic-level structure of the amorphous form of the drug atuliflapon, a 5-lipooxygenase activating protein (FLAP) inhibitor, via chemical-shift-driven NMR crystallography. The ensemble of preferred structures allows us to identify a number of specific conformations and interactions that stabilize the amorphous structure. These include preferred hydrogen-bonding motifs with water and with other drug molecules, as well as conformations of the cyclohexane and pyrazole rings that stabilize structure by indirectly allowing for optimization of hydrogen bonding.
Latest version: v1
Publication date: Jan 28, 2025
Pablo G. Lustemberg,
Chengwu Yang,
Yuemin Wang,
M. Veronica Ganduglia-Pirovano,
Christof Wöll
- The mechanisms underlying the reaction between carbon monoxide (CO) and activated dioxygen on metal oxide substrates to produce CO₂ remain poorly understood, particularly regarding the role of oxygen vacancies and the nature of the activated O₂ adsorbate. In this study, we present experimental findings from infrared reflection-absorption spectroscopy on a model system of bulk monocrystalline CeO₂(111). Contrary to expectations, exposing the reduced surface to dioxygen (O₂) at 80 K does not yield activated oxygen species, such as superoxo or peroxo. Notably, in the presence of adsorbed CO, an unexpected low-temperature oxidation reaction occurs, consuming CO while oxidizing the CeO₂ substrate. Since a direct reaction between impinging O₂ and adsorbed CO is unlikely at these low temperatures, a novel mechanism is proposed. Extensive spin-polarized density functional theory (DFT) calculations reveal that oxygen vacancies play a critical role in this low-temperature CO oxidation. ...
Latest version: v1
Publication date: Jan 28, 2025
Manaswini Sahoo,
Pietro Bonfà,
Amelia Elisabeth Hall,
Daniel A. Mayoh,
Laura Teresa Corredor,
Anja U. B. Wolter,
Bernd Büchner,
Geetha Balakrishnan,
Roberto De Renzi,
Giuseppe Allodi
- The discovery of chiral helical magnetism (CHM) in Cr1/3NbS2 and the stabilization of a chiral soliton lattice (CSL) has attracted considerable interest in view of their potential technological applications. However, there is an ongoing debate regarding whether the sister compound, Mn1/3NbS2, which shares the same crystal structure, exhibits similar nontrivial properties, which rely on the stabilization of the lack of inversion symmetry at the magnetic ion. In this study, we conduct a comprehensive investigation of the magnetically ordered states of both compounds, using 53Cr, 55Mn and 93Nb nuclear magnetic resonance. Our results, supported by density functional calculations, detect in a high quality single crystal of Cr1/3NbS2 all the signatures of the monoaxial CHM in a magnetic field, identifying it as a textbook NMR case. The detailed understanding of this prototypic behavior ...
Latest version: v2
Publication date: Jan 28, 2025
Giovanni Del Monte,
Emanuela Zaccarelli
- We perform extensive molecular dynamics simulations of an ensemble of realistic microgel particles in swollen conditions in a wide range of packing fractions ζ. We compare neutral and charged microgels, where we consider charge distribution adherent to experimental conditions. Through a detailed analysis of singleparticle behavior, we are able to identify the different regimes occurring upon increasing concentration: from shrinking to deformation and interpenetration, always connecting our findings with available experimental observations. We then link these single-particle features with the collective behavior of the suspension, finding evidence of a structural reentrance that has no counterpart in the dynamics. Hence, while the maximum of the radial distribution function displays a nonmonotonic behavior with increasing ζ, the dynamics, quantified by the microgels’ mean-squared displacement, always slows down. This behavior, at odds with the simple Hertzian model, can be ...
Latest version: v1
Publication date: Jan 24, 2025
Paolo Pegolo,
Enrico Drigo,
Federico Grasselli,
Stefano Baroni
- The determination of transport coefficients through the time-honoured Green-Kubo theory of linear response and equilibrium molecular dynamics requires significantly longer simulation times than those of equilibrium properties, while being further hindered by the lack of well-established data-analysis techniques to evaluate the statistical accuracy of the results. Leveraging recent advances in the spectral analysis of the current time series associated to molecular trajectories, we introduce a new method to estimate the full (diagonal as well as off-diagonal) Onsager matrix of transport coefficients from a single statistical model. This approach, based on the knowledge of the statistical distribution of the Onsager-matrix samples in the frequency domain, unifies the evaluation of diagonal (conductivities and viscosities) and off-diagonal (e.g., thermoelectric) transport coefficients within a comprehensive framework, significantly improving the reliability of transport coefficient ...
Latest version: v1
Publication date: Jan 23, 2025
Chong Wang,
Zeya Li,
Yingchun Cheng,
Xiao-Ji Weng,
Yeqiang Bu,
Kun Zhai,
Tianyu Xue,
Hongtao Yuan,
Anmin Nie,
Xiang-Feng Zhou,
Hongtao Wang,
Yongjun Tian,
Zhongyuan Liu
- Superelasticity, being a reversible nonlinear strain response to stress stimuli beyond the linear elastic regime, is always associated with phase transformations in its host materials, mostly metals or polymers. Theoretical rationale indicates that inorganic materials with covalent/ionic bonding normally have large energy barriers for reversible structural transitions and thus host less opportunity to achieve superelasticity. Here, we demonstrate a directional tensile superelasticity in ceramic crystal GeSe through an unconventional reversible shuffle twinning mechanism instead of martensitic phase transition. We observed, with in-situ mechanical transmission electron microscopy, an evolution in stress‒strain curve from the linear elastic behavior to a nonlinear superelastic plateau, and confirmed that such superelasticity appears simultaneously together with the generation of stripy-shaped twin domains along orientation. Theoretical calculations revealed that the shuffle ...
Latest version: v1
Publication date: Jan 23, 2025
Chenxiao Zhao,
Lin Yang,
João Henriques,
Mar Ferri-Cortés,
Gonçalo Catarina,
Carlo A. Pignedoli,
Ji Ma,
Xinliang Feng,
Pascal Ruffieux,
Joaquín Rossier,
Roman Fasel
- Antiferromagnetic Heisenberg chains exhibit two distinct types of excitation spectra: gapped for integer-spin chains and gapless for half-integer-spin chains. However, in finite-length half-integer-spin chains, quantization induces a gap, requiring precise control over sufficiently long chains to study its evolution. In a recent publication, we created length-controlled spin-1/2 Heisenberg chains by covalently linking olympicenes—Olympic ring-shaped magnetic nanographenes. With large exchange interactions, tunable lengths, and negligible magnetic anisotropy, this system is ideal for investigating length-dependent spin excitations, probed via inelastic electron tunneling spectroscopy. We observe a power-law decay of the lowest excitation energy with length L, following a 1/L dependence in the large-L regime, consistent with theory. For L=50, a V-shaped excitation continuum confirms gapless behavior in the thermodynamic limit. Additionally, low-bias current maps reveal the standing ...
Latest version: v1
Publication date: Jan 22, 2025
Jan P. Cuperus,
Arnold H. Kole,
Andrés R. Botello-Méndez,
Zeila Zanolli,
Daniel Vanmaekelbergh,
Ingmar Swart
- Magnet/superconductor hybrid systems have been put forward as a platform for realizing topological superconductivity. We investigated the heterostructure of ferromagnetic monolayer CrCl₃ and superconducting NbSe₂. Using low-temperature scanning tunneling microscopy, we observe topologically trivial Yu-Shiba-Rusinov (YSR) states localized at the edge of CrCl₃ islands. DFT simulations reveal that the Cr atoms at the edge have an enhanced d-orbital DOS close to the Fermi energy. This leads to an exchange coupling between these atoms and the substrate that rationalizes the edge-localization of the YSR states.
This dataset contains the first-principles calculations performed on a nanoribbon of CrCl₃ on NbSe₂ and the associated notebooks used to generate figures from this data.
Latest version: v1
Publication date: Jan 22, 2025
Guodong Zou,
Jinming Wang,
Yong Sun,
Weihao Yang,
Tingting Niu,
Jinyu Li,
Liqun Ren,
Zhi Wei Seh,
Qiuming Peng
- Sodium (Na) metal batteries are considered promising solutions for next-generation electrochemical energy storage because of their low costs and high energy densities. However, the slow Na dynamics result in unfavourable Na deposition and dendrite growth, which compromise cycling performance. Here we propose a nanotwinned alloy strategy prepared by high-pressure solid solution followed by Joule-heating treatment to address sluggish Na dynamics, achieving homogeneous Na deposition. By employing cost-effective Al-Si alloys for validation, Si solubility of 10 wt.% is extended through a high-pressure solid solution, and nanotwinned-Si particles, with a volume fraction of 82.7%, are subsequently formed through Joule-heating treatment. The sodiophilic nanotwinned-Si sites exhibit a high diffusion rate, which reduces the nondimensional electrochemical Damköhler number to far below 1, shifting the diffusion-controlled deposition behavior to reaction-controlled deposition. This transition ...
Latest version: v1
Publication date: Jan 16, 2025
Andrew Burgess,
Edward Linscott,
David O'Regan
- The piecewise linearity condition on the total energy with respect to the total magnetization of finite quantum systems is derived using the infinite-separation-limit technique. This generalizes the well-known constancy condition, related to static correlation error, in approximate density functional theory. The magnetic analog of Koopmans’ theorem in density functional theory is also derived. Moving to fractional electron count, the tilted-plane condition is derived, lifting certain assumptions in previous works. This generalization of the flat-plane condition characterizes the total energy surface of a finite system for all values of electron count N and magnetization M. This result is used in combination with tabulated spectroscopic data to show the flat-plane structure of the oxygen atom, among others. We find that derivative discontinuities with respect to electron count sometimes occur at noninteger values. A diverse set of tilted-plane structures is shown to occur in ...
Latest version: v1
Publication date: Jan 16, 2025
Robin Löfgren,
Kostiantyn Sopiha,
Sven Öberg,
Andreas Larsson
- To investigate charged defects in gapped materials by first-principles calculations, they must be charged by either adding/removing electrons or compensating donors/acceptors. The former approach is more common, but it is not without drawbacks. We tested the latter method for a collection of model systems consisting of charge-compensated point defects in diamond (NV/SiV-centers, substitutional nitrogen/phosphorous/oxygen/sulfur donors, and substitutional boron/beryllium acceptors), comparing the geometrical and electronic properties of the compensated defect pairs with those of the individual defects in charged supercells. We find that the charging by explicit donors/acceptors works well and can be advantageous if properly designed, although interpretation of the results can be challenging. In this archive, we share the final optimized geometries of all studied structural models (in CIF format).
Latest version: v1
Publication date: Jan 16, 2025
Leonardo Severini,
Letizia Tavagnacco,
Simona Sennato,
Erika Celi,
Ester Chiessi,
Claudia Mazzuca,
Emanuela Zaccarelli
- Polyelectrolyte complexes (PECs), formed via the self-assembly of oppositely charged polysaccharides, are highly valued for their biocompatibility, biodegradability, and hydrophilicity, offering significant potential for biotechnological applications. However, the complex nature and lack of insight at a molecular level into polyelectrolytes conformation and aggregation often hinders the possibility of achieving an optimal control of PEC systems, limiting their practical applications. To address this problem, an in-depth investigation of PECs microscopic structural organization is required. In this work, for the first time, a hybrid approach that combines experimental techniques with atomistic molecular dynamics simulations is used to elucidate, at a molecular level, the mechanisms underlying the aggregation and structural organization of complexes formed by gellan and chitosan, i.e. PECs commonly used in food technology. This combined analysis reveals a two-step complexation ...
Latest version: v1
Publication date: Jan 16, 2025
Mohamed S. Abdallah,
Alfredo Pasquarello
- Using vertex-corrected quasiparticle self-consistent GW schemes, we address the electronic structure of two manganese dioxide polymorphs, α-MnO₂ and β-MnO₂. In particular, we determine the fundamental band gaps, the macroscopic dielectric constants, the magnetic moments of the Mn atoms, the band structures and the associated densities of states. Additionally, we obtain the imaginary component of the dielectric function ε₂(𝜔) from the solution of the Bethe–Salpeter equation. For β-MnO₂, we record overall good agreement when comparing the density of states with XPS/BIS spectra and the dielectric function ε₂(𝜔) with optical response spectra. Applied to α-MnO₂, whose pristine bulk structure is poorly characterized, our work provides a prediction at the same level of theory. The quality of the achieved description is further supported by comparisons with experimental spectra of nanostructured and doped variants. This study demonstrates that state-of the-art GW methods successfully ...
Latest version: v1
Publication date: Jan 14, 2025
John Ingall,
Edward Linscott,
Nicola Colonna,
Alister Page,
Vicki Keast
- Metal halide perovskites (MHPs) demonstrate an exceptional combination of properties. Rapid progress has extended their application beyond solar cells, light-emitting diodes, photodetectors, and lasers to include memristors, artificial synapse devices, and pressure induced emission. In particular, the vacancy-ordered double perovskite Cs₂TiBr₆ has been identified as a promising material. The effective characterization of MHPs requires accurate and efficient methods for the calculation of electronic structure. Koopmans compliant (KC) functionals are an accurate and computationally efficient alternative to many-body perturbation theory using the GW approximation but have yet only been validated on a small number of simple materials. In this work, KC functionals were applied to the more complex case of Cs₂TiBr₆ and gave a zero-temperature fundamental gap of 4.28 eV, in close agreement with the value of 4.44 eV obtained using the accurate, but more computationally expensive, evGW₀ ...
Latest version: v1
Publication date: Jan 14, 2025
Kamil Iwanowski,
Gábor Csányi,
Michele Simoncelli
- Understanding how the vibrational and thermal properties of solids are influenced by atomistic structural disorder is of fundamental scientific interest, and paramount to designing materials for next-generation energy technologies. While several studies indicate that structural disorder strongly influences the thermal conductivity, the fundamental physics governing the disorder-conductivity relation remains elusive. Here we show that order-of-magnitude, disorder-induced variations of conductivity in network solids can be predicted from a bond-network entropy, an atomistic structural descriptor that quantifies heterogeneity in the topology of the atomic-bond network. We employ the Wigner formulation of thermal transport to demonstrate the existence of a relation between the bond-network entropy, and observables such as smoothness of the vibrational density of states (VDOS) and macroscopic conductivity. We also show that the smoothing of the VDOS encodes information about the ...
Latest version: v1
Publication date: Jan 12, 2025
Rowan R. Katzbaer,
Simon Gelin,
Monica J. Theibault,
Mohammed M. Khan,
Cierra Chandler,
Nicola Colonna,
Zhiqiang Mao,
Héctor D. Abruña,
Ismaila Dabo,
Raymond E. Schaak
- Materials that efficiently promote the thermodynamically uphill water-splitting reaction under solar illumination are essential for generating carbon-free (“green”) hydrogen. Mapping out the combinatorial space of potential photocatalysts for this reaction can be expedited using data-intensive materials exploration. The calculated band gaps and band alignments can serve as key indicators and metrics to computationally screen photoactive materials. Ternary main-group metal sulfides containing p- and s-block elements represent a promising, albeit underexplored, class of photocatalysts. Here, we computationally screen 86 candidate ternary main-group metal sulfides containing p- and s-block elements. By validating electronic structure predictions against experimental band gaps and band edges for synthetically accessible materials, we propose eight potential photocatalysts. Using computed Pourbaix diagrams, we further narrowed the candidate pool to four materials based on the predicted ...
Latest version: v1
Publication date: Jan 10, 2025
Brenda de Souza Ferrari,
Ronaldo Giro,
Mathias B. Steiner
- Polymers are versatile materials with a wide range of applications. The improvement of polymer properties rises the importance on the way that the repeating units are connected (head-to-tail,head-to-head,tail-to-tail) to build the polymer structure since it directly influences the morphology, chain topology and consequently its properties. Artificial intelligence (AI) based approaches are beginning to impact several domains of human life, science and technology. Polymer informatics is one such domain where AI and machine learning (ML) tools are being used in the efficient development, design and discovery of polymer. One key enabling factor for the essential foundations for Polymer Informatics is the machine-readable polymer representation. Polymer have been represented in a string format with special characters used to tag the head and tail positions indicating where the linking bond happens between repeat units. Available tools to assign the head and tail position limits its ...
Latest version: v1
Publication date: Jan 10, 2025
Nestor Merino-Diez,
Raymond Amador,
Samuel T. Stolz,
Daniele Passerone,
Roland Widmer,
Oliver Gröning
- Homogenous enantioselective catalysis is nowadays the cornerstone in the manufacturing of enantiopure substances, but its technological implementation suffers from well-known impediments like the lack of endurable catalysts exhibiting long-term stability. The catalytically active intermetallic compound Palladium-Gallium (PdGa), conserving innate bulk chirality on its surfaces, represent a promising system to study asymmetric chemical reactions by heterogeneous catalysis, with prospective relevance for industrial processes. In a recent publication we investigate the adsorption of 10,10′-dibromo-9,9′-bianthracene (DBBA) on the PdGa:A(-1-1-1) Pd3-terminated surface by means of scanning tunneling microscopy (STM) and spectroscopy (STS). A highly enantioselective adsorption of the molecule evolving into a near 100% enantiomeric excess below room temperature is observed. This exceptionally high enantiomeric excess is attributed to temperature activated conversion of the S to the R ...
Latest version: v1
Publication date: Jan 09, 2025
Mickael L. Perrin,
Anooja Jayaraj,
Bhaskar Ghawri,
Kenji Watanabe,
Takashi Taniguchi,
Daniele Passerone,
Michel Calame,
Jian Zhang
- Twisted van der Waals heterostructures have recently emerged as a versatile platform for engineering interaction-driven, topological phenomena with a high degree of control and tunability. Since the initial discovery of correlated phases in twisted bilayer graphene, a wide range of moiré materials have emerged with fascinating electronic properties. While the field of twistronics has rapidly evolved and now includes a range of multi-layered systems, moiré systems comprised of double trilayer graphene remain elusive. Here, we report electrical transport measurements combined with tight-binding calculations in twisted double trilayer graphene (TDTLG). We demonstrate that small-angle TDTLG (~1.7−2.0ᵒ) exhibits an intrinsic bandgap at the charge neutrality point. Moreover, by tuning the displacement field, we observe a continuous insulator-semimetal-insulator transition at the CNP, which is also captured by tight-binding calculations. These results establish TDTLG systems as a highly ...
Latest version: v1
Publication date: Jan 08, 2025
Sylvian Cadars,
Olivier Masson,
Jean-Paul Laval,
Firas E. Shuaib,
Gaelle Delaizir,
Andrea Piarristeguy,
Assil Bouzid
- A semi-automated protocol largely based on AiiDA has been developed and exploited to explore the yet-unsolved crystal structure of the recently-discovered AsTe₃ material with potential thermoelectric applications due to its ultralow thermal conductivity. The workflow involves different steps of increasing precision and computational cost, in a sequential approach to generate, refine and evaluate model AsTe₃ structures based on supercells of elemental-Te from the stand point of As/Te chemical disorder. Our studies shed light on the structural complexity that has prevented, to this day, a direct structure determination of the recently-discovered crystalline AsTe₃ material, despite the new synthesis protocol that has led to its obtention in a pure and fully crystalline phase, by congruent crystallization from the parent AsTe₃ glass. Structural models of crystalline AsTe₃ reveal a composition based on an intergrowth of subnanometric As₂Te₃ and Te domains with potentially defected ...
Latest version: v1
Publication date: Jan 07, 2025
Wei Bin How,
Sanggyu Chong,
Federico Grasselli,
Kevin K. Huguenin-Dumittan,
Michele Ceriotti
- The electronic density of states (DOS) provides information regarding the distribution of electronic energy levels in a material, and can be used to approximate its optical and electronic properties and therefore guide computational material design. Given its usefulness and relative simplicity, it has been one of the first electronic properties used as target for machine-learning approaches going beyond interatomic potentials. A subtle but important point, well-appreciated in the condensed matter community but usually overlooked in the construction of data-driven models, is that for bulk configurations the absolute energy reference of single-particle energy levels is ill-defined. Only energy differences matter, and quantities derived from the DOS are typically independent on the absolute alignment. We introduce an adaptive scheme that optimizes the energy reference of each structure as part of the training process, and show that it consistently improves the quality of ML models ...
Latest version: v4
Publication date: Jan 07, 2025
Ruslan Mushkaev,
Francesco Petocchi,
Viktor Christiansson,
Philipp Werner
- The multi-tier GW+EDMFT scheme is an ab-initio method for calculating the electronic structure of correlated materials. While the approach is free from ad-hoc parameters, it requires a selection of appropriate energy windows for describing low-energy and strongly correlated physics. In this study, we test the consistency of the multi-tier description by considering different low-energy windows for a series of cubic SrXO₃ (X = V, Cr, Mn) perovskites. Specifically, we compare the 3-orbital t2g model, the 5-orbital t2g + eg model, the 12-orbital t2g + Op model, and (in the case of SrVO₃) the 14-orbital t2g + eg + Op model and compare the results to available photoemission and X-ray absorption measurements. The multi-tier method yields consistent results for the t2g and t2g + eg low-energy windows, while the models with Op states produce stronger ...
Latest version: v1
Publication date: Jan 07, 2025
Karim Elgammal,
Marc Maußner
- This dataset supports a systematic implementation of hybrid quantum-classical computational methods for investigating corrosion inhibition mechanisms on aluminum surfaces. The work presents an integrated workflow combining density functional theory (DFT) with quantum algorithms through an active space embedding scheme, specifically applied to studying 1,2,4-Triazole and 1,2,4-Triazole-3-thiol inhibitors on Al111 surfaces. The methodology employs the orb-d3-v2 machine learning potential for rapid geometry optimizations, followed by accurate DFT calculations using CP2K with PBE functional and Grimme's D3 dispersion corrections. Our implementation leverages the ADAPT-VQE quantum algorithm with benchmarking against classical DFT calculations, achieving binding energies of -0.386 eV and -1.279 eV for 1,2,4-Triazole and 1,2,4-Triazole-3-thiol, respectively.
Latest version: v1
Publication date: Dec 30, 2024
Tsuneya Yoshida,
Song-bo Zhang,
Titus Neupert
- This file contains all the data, as well as the code necessary to reproduce the exact diagonalization calculations in Phys. Rev. Lett. 133, 076502 (2024) in which the phenomenon of a non-Hermitian Mott skin effect is introduced theoretically. Skin effects are a key differentiating feature of (one-dimensional) non-Hermitian systems, and are characterized by the exponential accumulation of charge towards one side of the system in all its eigenstates. It appears in noninteracting systems. This work finds a novel analogous effect which is specific to interacting quantum particles, where the particle density is constant, but a flavour/spin degree of freedom shows the exponential localization. This is demonstrated with exact diagonalization calculations of the non-Hermitian many-body Hamiltonian as well as the time-evolution of the Lindbladian.
Latest version: v1
Publication date: Dec 26, 2024
Marija Stojkovic,
Edward Linscott,
Nicola Marzari
- Photocatalytic water splitting has attracted considerable attention for renewable energy production. Since the first reported photocatalytic water splitting by titanium dioxide, this material remains one of the most promising photocatalysts, due to its suitable band gap and band-edge positions. However, predicting both of these properties is a challenging task for existing computational methods. Here we show how Koopmans spectral functionals can accurately predict the band structure and level alignment of rutile, anatase, and brookite TiO₂ using a computationally efficient workflow that only requires (a) a DFT calculation of the photocatalyst/vacuum interface and (b) a Koopmans spectral functional calculation of the bulk photocatalyst. The success of this approach for TiO₂ suggests that this strategy could be deployed for assessing the suitability of novel photocatalyst candidates.
This record contains for each polymorph: (a) a calculation of a slab; (b) KI and pKIPZ band structure calculation of the bulk system.
Latest version: v1
Publication date: Dec 23, 2024
Arnaud Lorin,
Thomas Bischoff,
Alexey Tal,
Alfredo Pasquarello
- Within many-body perturbation theory, we calculate band offsets for a set of epitaxial interfaces, including AlP/GaP, AlAs/GaAs, Ge/AlAs, Ge/GaAs, Ge/ZnSe, Si/GaP, ZnSe/GaAs, and CaF2/Si. We consider various quasiparticle self-consistent 𝐺𝑊 schemes with or without including vertex functions. In particular, we consider two types of effective vertex functions complying with the Ward identity in the long range, one of which additionally carries a short-range part, which has been found to improve ionization potentials. The obtained band offsets correspond to model interface structures that match the experimental lattice parameters of the bulk components. Strain, zero-phonon renormalization, and spin-orbit coupling effects are properly accounted for. For the band offsets of the semiconductor-semiconductor interfaces, all the self-consistent 𝐺𝑊 schemes yield similar mean absolute errors on the order of 0.2 eV. In the case of the CaF2/Si interface, the calculated band offsets show ...
Latest version: v1
Publication date: Dec 20, 2024
Longze Li,
John Merickel,
Yalei Tang,
Rongjie Song,
Joshua Rittenhouse,
Aleksandar Vakanski,
Fei Xu
- The dataset provides records of tensile properties of nuclear structural materials. The focus is on studying the influence of specimen dimensions and geometry on mechanical properties such as yield strength, ultimate tensile strength, uniform elongation, and total elongation. The dataset was created through an extensive literature review of scientific articles and databases. The search inclusion criteria targeted peer-reviewed studies on tensile testing of sub-sized specimens, providing quantitative data on tensile properties relative to specimen size. The extracted data points from the literature review were organized into a tabular format database containing 1,070 tensile testing records with 54 parameters, including material type and composition, manufacturing information, irradiation conditions, specimen size and dimensions, and tensile properties. Materials science experts conducted systematic checks to validate the collected data, ensuring accuracy in the material type, ...
Latest version: v3
Publication date: Dec 20, 2024
Isshu Lee,
John W. Merickel,
Yugandhar Kasala Sreenivasulu,
Fei Xu,
Yalei Tang,
Joshua E. Rittenhouse,
Aleksandar Vakanski,
Rongjie Song
- The dataset contains records of Charpy V-notch impact tests of nuclear structural materials. The focus is on studying the influence of specimen dimensions and geometry on Charpy impact test properties. The dataset was created through an extensive literature review of scientific articles. The extracted data points from the literature review are organized into a tabular format database containing 4,775 test records with 55 parameters, including material type and composition, manufacturing information, irradiation conditions, specimen size and dimensions, and Charpy properties. Materials science experts conducted systematic validation checks to ensure the accuracy of the information related to material type, manufacturing processes, treatment methods, chemical composition, testing conditions, as well as other pertinent information.
Latest version: v1
Publication date: Dec 19, 2024
Tao Zhang,
Qingyi Liu,
Haoming Bao,
Mingyue Wang,
Nana Wang,
Bao Zhang,
Hong Jin Fan
- Here, we develop a self-assembly technique to synthesize 1-nm-thick rutile-structured high-entropy oxides (RuIrFeCoCrO₂) from naked metal ions assembly and oxidation at air-molten salt interface. The RuIrFeCoCrO₂ only requires an overpotential of 185 mV at 10 m A cm⁻² and maintains the high activity for over 1000 hours in an acidic electrolyte via the adsorption evolution mechanism. In this dataset, we calculated the desolvation coefficient (D) of various cations in aqueous solution and molten salt. In molten salt, the corresponding D for metal ions is higher by several orders of magnitude compared to that in water, which allows metal ions to become freely moving ions. We also conducted DFT calculations to gain insight to the structural stability and reaction mechanism of this HEO. The results show that the reaction mechanism changes from LOM (RuO₂) to AEM (RuIrFeCoCrO₂).
Latest version: v1
Publication date: Dec 18, 2024
Sara Marchio,
Francesco Buonocore,
Simone Giusepponi,
Massimo Celino
- Functionalizing Silicon Nanowires (SiNWs) through covalent attachment of organic molecules offers diverse advantages, including surface passivation, introduction of new functionalities, and enhanced material performance in applications like electronic devices and biosensors. Given the wide range of available functional molecules, systematic large-scale screening is crucial. Therefore, we developed an automated computational workflow using Python scripts in conjunction with the AiiDa framework to explore structural configurations of functional molecules adsorbed onto silicon surfaces. This workflow generates multiple adhesion configurations corresponding to different binding orientations using surface and functional molecule structures as inputs.
This dataset contains data related to the structural optimization of molecules with single, double, and triple carbon-carbon bonds attached to the nanowire surface in various adhesion configurations. We describe the chemisorption on ...
Latest version: v3
Publication date: Dec 18, 2024
Jiaqi Zhou,
Samuel Poncé,
Jean-Christophe Charlier
- Spin Hall effect (SHE) in two-dimensional (2D) materials is promising to effectively manipulate spin angular momentum and identify topological properties. In this work, we implemented an automated Wannierization with spin-orbit coupling on 426 non-magnetic monolayers including 210 metal and 216 insulators. Intrinsic spin Hall conductivity (SHC) has been calculated to find candidates exhibiting novel properties. We discover that Y₂C₂I₂ has an unconventional SHE with canted spin due to low crystal symmetry, Ta₄Se₂ is a metallic monolayer with exceptionally high SHC, and the semi-metal Y₂Br₂ possesses efficient charge-to-spin conversion induced by anti-crossing in bands. Moreover, quantum spin Hall insulators are investigated for quantized SHC. The present work provides a high-quality Wannier Hamiltonian database of 2D materials, and paves the way for the integration of 2D materials into high-performance and low-power-consumption spintronic devices.
Latest version: v1
Publication date: Dec 18, 2024
Bao Zhang,
Jia Yao,
Chao Wu,
Yuanjian Li,
Jia Liu,
Jiaqi Wang,
Tao Xiao,
Tao Zhang,
Daqian Cai,
Jiawen Wu,
Zhi Wei Seh,
Shibo Xi,
Hao Wang,
Wei Sun,
Houzhao Wan,
Hong Jin Fan
- Here we present an on-demand strategy for electrolytes design to surpass 99.9% Coulombic efficiency (CE) in zinc metal anode. This strategy synergizes various effects by specifically targeting the two critical factors: plating morphology and the anode-electrolyte interface. In this dataset, we simulated the solvation structures and bilayer structures of various electrolytes by molecular dynamics simulations. We found Triethyl phosphate and dimethylformamide can induce the free-water-poor inner Helmholtz plane and reduce the interfacial water activity. Furthermore, the MD results imply that the dual-salt introduces more anions into the Zn2+ primary solvation sheath, and the DMF co-solvent is also able to enter the solvation sheath.
Latest version: v1
Publication date: Dec 13, 2024
