Temperature dependence on phase evolution in the BaTiO3 polytypes studied using ab initio calculations
Abstract: Identifying the forces that drive a temperature-induced phase transition is always challenging in the prospect of the first-principles methods. Herein, we perform a first-principles study of the temperature effects on structural, energetic, electronic, and vibrational properties of four BaTiO3 polymorphs using quasi-harmonic approximations. Study of the stability between these four phases, which we break into contributions arising from the vibration of the lattice, electronic structure, and volume expansion/contraction, is helpful to confirm the sequence of phase transitions as cubic -> tetragonal -> orthorhombic -> rhombohedral, as well as its transition temperatures. A general mechanism was proposed based on the combination between structural distortions at [TiO6] clusters, vibrational characteristics, and electronic structure. These findings confirm the power of quasi-harmonic approximations to disclose the main fingerprints associated with both thermic and mechanical phase transitions, serving as a guide for further theoretical studies.
Author(s): Oliveira, MC; Ribeiro, RAP; Longo, E; Bomio, MRD; Motta, FV; de Lazaro, SR
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
Volume: 120 Edition: 1 Published: JAN 1 2020
DOI: 10.1002/qua.26054
