Computational study of (111) epitaxially strained ferroelectric perovskites BaTiO3 and PbTiO3

TL;DR

This study uses density-functional theory to analyze how (111) epitaxial strain affects phase transitions and polarization in ferroelectric BaTiO3 and PbTiO3 perovskites, revealing distinct strain-induced behaviors.

Contribution

It provides a detailed computational analysis of strain-induced phase transitions in BaTiO3 and PbTiO3, highlighting differences in polarization response under (111) epitaxial strain.

Findings

PbTiO3 undergoes multiple phase transitions with strain, polarization remains nearly constant.

BaTiO3's polarization is suppressed under compressive strain, leading to a non-polar phase.

Distinct phase transition pathways are identified for the two materials under strain.

Abstract

The phase transition behaviour of PbTiO3 and BaTiO3 under (111) epitaxial strain is investigated using density-functional theory calculations. From tensile strains of +0.015 to compressive strains of -0.015, PbTiO3 undergoes phase transitions from C2 through two Cm phases and then to R3m. The total polarisation is found to be almost independent of strain. For the same range of strains BaTiO3 undergoes phase transitions from a single Cm phase, through R3m and then to R-3m. In this case the application of compressive strain inhibits and then completely suppresses the polarisation on transition to the non-polar R-3m phase.