Tunable oxygen vacancy configuration by strain engineering in perovskite ferroelectrics from first-principles study

Abstract

Comprehensive first-principle calculations indicate that the oxygen vacancy (VO) configuration of a prototypical perovskite oxide PbTiO3 (PTO) can be tuned by strain engineering. Remarkably, we found that VO located along the c axis (Vc), normally resulting in a polarization-harming tail-to-tail domain configuration in strain-free PTO (Vcud), can be readily tuned to a polarization-harmless head-to-tail domain configuration (Vcsw) by applying an ab-biaxial compressive strain of 3%. Also, VO located in the ab-plane (Vab), another type of polarization-harmless vacancy, can be stabilized by applying a compressive strain of 2%.