Garu Gebreyesus^1*, Lorenzo Bastonero^2*, Michele Kotiuga^3*, Nicola Marzari^2,3*, Iurii Timrov^3,4*

1 Department of Physics, School of Physical and Mathematical Sciences, College of Basic and Applied Sciences, University of Ghana, Ghana

2 University of Bremen, U Bremen Excellence Chair, Bremen Center for Computational Materials Science, and MAPEX Center for Materials and Processes, University of Bremen, D-28359 Bremen, Germany

3 Theory and Simulation of Materials (THEOS), and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland

4 Present address: Laboratory for Materials Simulations (LMS), Paul Scherrer Institut (PSI), CH-5232 Villigen PSI, Switzerland

* Corresponding authors emails: ghagoss@ug.edu.gh, lbastone@hmi.uni-bremen.de, michele.kotiuga@epfl.ch, nicola.marzari@epfl.ch, iurii.timrov@psi.ch

DOI10.24435/materialscloud:vz-7q [version v1]

Publication date: Nov 30, 2023

How to cite this record

Garu Gebreyesus, Lorenzo Bastonero, Michele Kotiuga, Nicola Marzari, Iurii Timrov, Understanding the role of Hubbard corrections in the rhombohedral phase of BaTiO₃, Materials Cloud Archive 2023.187 (2023), https://doi.org/10.24435/materialscloud:vz-7q

Description

We present a first-principles study of the low-temperature rhombohedral phase of BaTiO₃ using Hubbard-corrected density-functional theory. By employing density-functional perturbation theory, we compute the onsite Hubbard U for Ti(3d) states and the intersite Hubbard V between Ti(3d) and O(2p) states. We show that applying the onsite Hubbard U correction alone to Ti(3d) states proves detrimental, as it suppresses the Ti(3d)-O(2p) hybridization and drives the system towards a cubic phase. Conversely, when both onsite U and intersite V are considered, the localized character of the Ti(3d) states is maintained, while also preserving the Ti(3d)-O(2p) hybridization, restoring the rhombohedral phase of BaTiO₃. The generalized PBEsol+U+V functional yields good agreement with experimental results for the band gap and dielectric constant, while the optimized geometry is slightly less accurate compared to PBEsol. Zone-center phonon frequencies and Raman spectra are found to be significantly influenced by the underlying geometry. PBEsol and PBEsol+U+V provide satisfactory agreement with the experimental Raman spectrum when the PBEsol geometry is used, while PBEsol+U Raman spectrum diverges strongly from experimental data highlighting the adverse impact of the U correction alone in BaTiO₃. Our findings underscore the promise of the extended Hubbard PBEsol+U+V functional with first-principles U and V for the investigation of other ferroelectric perovskites with mixed ionic-covalent interactions.

Materials Cloud sections using this data

Files

File name	Size	Description
Files.tar MD5md5:b1326fb2773c9aebe2359b5af5461219	26.7 MiB	Collection of all files which were used to produce the data of the paper: input files, output files, references to codes which were used, etc.
README_Files.txt MD5md5:0942cc77c7bd68e2845880536dfad5bd	5.8 KiB	The README_Files.txt file describes the content of the compressed file "Files.tar"
BaTiO3.aiida MD5md5:966defa227374ee19994009ffebfd0a1 Open this AiiDA archive on renkulab.io (https://renkulab.io/)	84.7 MiB	AiiDA data for BaTiO3
README_AiiDA.txt MD5md5:a698e98a00198f71cef6b5e28271d5cc	4.3 KiB	The README_AiiDA.txt file describes the content of the file "BaTiO3.aiida"

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External references

Keywords

BaTiO3 DFT+U+V DFT+U phonons Raman spectra CSCS MARVEL/P4