Strain effects on formation and migration energies of oxygen vacancy in perovskite ferroelectrics: A first-principles study

Oxygen vacancies (V-O) and their migration and redistribution are believed to be the dominant factors resulting in the degradation of ferroelectrics. Thus, suppressing the formation and mobility of V-O is quite crucial for the physical properties of ferroelectric materials. In this paper, the ab-biaxial strain effects on V-O and their migration process in prototype perovskite ferroelectric BaTiO3 were studied by first principles total energy calculation. It is found that the formation energies for the two symmetrically inequivalent V-O are enhanced under compressive strain. V-O migration path between V-c (V-O is located along the c-axis) and V-ab (V-O is located in the ab-plane) shows an S shape. The V-O migration barrier between V-c and V-ab is enhanced by the compressive strain while lowered by the tensile strain. These results suggest that the ferroelectricity degradation induced by V-O and their migration can be effectively mitigated by applying compressive strain. (C) 2013 AIP Publishing LLC.