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arXiv · 1411.4211

Noncentrosymmetric structural transitions in ultrashort ferroelectric AGaO$_{3}$/A'GaO$_{3}$ superlattices

Nayoung Song·James M. Rondinelli·Bog G. Kim
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Abstract

The effect of octahedral tilting on the acentric structural transitions in AGaO$_{3}$/A'GaO$_{3}$ [001], [110], and [111] superlattices (A, A' = La, Pr, Nd) is studied using density functional theory. We find the displacive transitions are driven by two octahedral rotations modes (a$^{-}$a$^{-}$c$^{0}$ and a$^{0}$a$^{0}$c$^{+}$ tilting), with amplitudes that depend on the A and A' chemistry and cation ordering direction. We find the ground states structures of the [001] and [111] ordered superlattices are polar. The coupling of octahedral tilting modes through a hybrid improper ferroelectric mechanism induces the polar displacements and produces the macroscopic electric polarizations.

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Nayoung Song, James M. Rondinelli, Bog G. Kim. 2014-11-16. Noncentrosymmetric structural transitions in ultrashort ferroelectric AGaO$_{3}$/A'GaO$_{3}$ superlattices. https://doi.org/10.1103/physrevb.91.134104

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