First-principles study of epitaxial strain in perovskites

Abstract

Using an extension of a first-principles method developed by King-Smith and Vanderbilt [Phys. Rev. B, 49, 5828 (1994)], we investigate the effects of in-plane epitaxial strain on the ground-state structure and polarization of eight perovskite oxides: $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_{3}$, $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$, $\mathrm{Ca}\mathrm{Ti}{\mathrm{O}}_{3}$, $\mathrm{K}\mathrm{Nb}{\mathrm{O}}_{3}$, $\mathrm{Na}\mathrm{Nb}{\mathrm{O}}_{3}$, $\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$, $\mathrm{Pb}\mathrm{Zr}{\mathrm{O}}_{3}$, and $\mathrm{Ba}\mathrm{Zr}{\mathrm{O}}_{3}$. In addition, we investigate the effects of a nonzero normal stress. The results are shown to be useful in predicting the structure and polarization of perovskite oxide thin films and superlattices.