Ab initio prediction of structural phase-transition temperature of SrTiO$_3$ from finite-temperature phonon calculation

Abstract

o̧pyright 2019 The Ceramic Society of Japan. All rights reserved. The cubic-to-tetragonal phase transition temperature Tc of SrTiO3 is predicted from first-principles anharmonic lattice dynamics simulation. By using the self-consistent phonon approach, we compute finite-temperature phonon dispersion of cubic and tetragonal SrTiO3. By comparing the Helmholtz free energies of the two phases calculated with anharmonic effects included, we obtain Tc3 80 K, which is comparable with the experimental value of 105 K. In addition, we show that the nuclear quantum effect is significant for predicting Tc. Our approach is efficient and provides a convenient way of predicting the phase stability of solids including ceramics, where the conventional approach based on the harmonic approximation often breaks down.

Terumasa Tadano

Researcher of Materials Science

My research interests include development of computational methods and softwares for predicting thermal properties of solids, and application of machine-learning methods to material science study