Michele Kotiuga^1,2*, Samed Halilov³, Boris Kozinsky^4,5*, Marco Fornari^6*, Nicola Marzari^1,2*, Giovanni Pizzi^1,2*

1 Theory and Simulations of Materials (THEOS), École Polytechnique Fedérale de Lausanne, 1015 Lausanne, Switzerland

2 National Centre for Computational Design and Discovery of Novel Materials (MARVEL), 1015 Lausanne, Switzerland

3 Designed Material Technologies, LLC, P.O. Box 14548, Richmond, VA 23221-9998, US

4 John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138, USA

5 Robert Bosch LLC, Research and Technology Center, Cambridge, Massachusetts 02142, USA

6 Department of Physics and Science of Advanced Materials Program, Central Michigan University, Mt. Pleasant, Michigan 48859, US

* Corresponding authors emails: michele.kotiuga@epfl.ch, bkoz@seas.harvard.edu, forna1m@cmich.edu, nicola.marzari@epfl.ch, giovanni.pizzi@epfl.ch

DOI10.24435/materialscloud:pg-50 [version v1]

Publication date: Jul 12, 2021

How to cite this record

Michele Kotiuga, Samed Halilov, Boris Kozinsky, Marco Fornari, Nicola Marzari, Giovanni Pizzi, A microscopic picture of paraelectric perovskites from structural prototypes, Materials Cloud Archive 2021.104 (2021), doi: 10.24435/materialscloud:pg-50.

Description

This work details how to determine structural prototypes for the cubic perovskite structure that are used to study the B-site displacements in the cubic, paraelectric phase. Car-Parrinello MD simulations of cubic barium titanate (BaTiO3) show the titanium displacements from the undistorted cubic structure. Using a systematic symmetry analysis we construct microscopic templates, i.e. representative structural models in the form of supercells that satisfy a desired point symmetry but are built from the combination of lower-symmetry primitive cells. Density functional theory calculations, using the microscopic templates as starting structures for a relaxation, are carried out to find structural prototypes of BaTiO3 with local polar distortions but with cubic point symmetry. The stability of these structures is studied as a function of volume and with respect to the zone-boundary phonons of pristine cubic BaTiO3. The stable distortions patterns for BaTiO3 are investigated for other titanates and for a handful of niobates and zirconates.

Materials Cloud sections using this data

Files

File name	Size	Description
README.txt MD5md5:d990eba789b18b991aad5cba38edffee	1.1 KiB	Description of 'Figures_main', 'Figures_SI', 'microscopic_templates', 'materials_displacements', 'materials_5atom_phonon' and 'pseudopotenials'
Figures_main.zip MD5md5:3d961798e928c68d74e87cc97a048729	314.6 MiB	Contains directories with a brief README and the data to reproduce the figures in the main text, or directions to the relevant directory
Figures_SI.tar.gz MD5md5:d5de060f9d447b88d4ef8a2c60b1866f	239.1 MiB	Contains directories with a brief README and the data to reproduce the figures in the supplemental, or directions to the relevant directory
microscopic_templates.tar.gz MD5md5:f0ed9c7b434b933dc4124f3100f8216b	8.6 KiB	Contains a cif for a representation of each of the 27 distinct cubic microscopic templates of spacegroup 221 with occupied Wyckoff positions: 1a, 1b, 3c. In this representation BaTiO3 is used where Ba occupies the 1a, Ti the 1b, and O the 3c Wyckoff position in the high-symmetry phase.
materials_displacements.zip MD5md5:de1207ab0f532282f4733e8d039ad45d	18.2 MiB	his directory contains the output of the pw.x relax calculations of the 4+4 and 2+6 displacement patterns with fixed lattice parameters.
materials_5atom_phonons.zip MD5md5:785730b6237f72e7297577ad43498877	8.4 MiB	This directory contains the phonon calculations for the 5 atom cubic structures
pseudopotentials.zip MD5md5:ff653596767e303f7f23ba228810a2c7	27.2 MiB	contains the pseudopotentials used in the calculations

License

Files and data are licensed under the terms of the following license: Creative Commons Attribution 4.0 International.
Metadata, except for email addresses, are licensed under the Creative Commons Attribution Share-Alike 4.0 International license.

External references

Keywords

Paraelectricity perovskite group-subgroup relations MARVEL/OSP MaX