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arXiv · 0904.2118

Strain-induced ferroelectricity in CaTiO$_3$ from first principles

C. -J. Eklund·C. J. Fennie·K. M. Rabe
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Abstract

First principles calculations are used to investigate the effects of epitaxial strain on the structure of the perovskite oxide CaTiO$_3$, with particular focus on the stabilization of a ferroelectric phase related to a polar instability hidden in the orthorhombic equilibrium bulk $Pbnm$ structure but found in previous first-principles studies of the ideal cubic perovskite high-symmetry reference structure. At 1.5% strain, we find an epitaxial orientation transition between the $ab$-$ePbnm$ phase, favored for compressive strains, and the $c$-$ePbnm$ phase. For larger tensile strains, a polar instability develops in the $c$-$ePbnm$ phase and an epitaxial-strain-induced ferroelectric phase is obtained with polarization along a $<$110$>$ direction with respect to the primitive perovskite lattice vectors of the square substrate.

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C. -J. Eklund, C. J. Fennie, K. M. Rabe. 2009-04-14. Strain-induced ferroelectricity in CaTiO$_3$ from first principles. https://doi.org/10.1103/physrevb.79.220101

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