We use first principles density functional theory calculations to investigate the effect of biaxial strain in the low-temperature structural and ferroelectric properties of [111]-oriented SrTiO3. We find that [111] biaxial strain, achievable by coherent epitaxial growth along the [111] direction, induces structural distortions in SrTiO3 that are not present in either bulk or [001]-oriented SrTiO3. Under [111] biaxial strain, SrTiO3 displays ferroelectricity at tensile strain, and paraelectricity at compressive strain. We compute the phonon spectrum and macroscopic polarization of SrTiO3 as a function of [111] biaxial strain, and relate our results to the predictions of the free energy phenomenological model of Pertsev, Tagantsev and Setter [Phys. Rev. B 61, 825 (2000); Phys. Rev. B 65, 219901 (2002)].
@article{arxiv.1811.02713,
title = {Ferroelectricity in [111]-oriented epitaxially strained SrTiO$_3$ from first principles},
author = {Sebastian E. Reyes-Lillo and Karin M. Rabe and Jeffrey B. Neaton},
journal= {arXiv preprint arXiv:1811.02713},
year = {2019}
}