We model short-period superlattices of WO3 and ReO3 with first-principles calculations. In fully-relaxed superlattices, we observe that octahedral tilts about an axis in the planes of the superlattices do not propagate from one material, despite the presence of the corner-shared oxygen atoms. However, we find that octahedral rotation is enhanced within WO3 layers in cases in which strain couples with native antiferroelectric displacements of tungsten within their octahedral cages. Resulting structures remain antiferroelectric with low net global polarization. Thermodynamic analysis reveals that superlattices with sufficiently thick ReO3 layers, the absolute number being three or more layers and the Re fraction ≥50%, tend to be more stable than the separated material phases and also show enhanced octahedral rotations in the WO3 layers.
@article{arxiv.1405.3699,
title = {Coupling between octahedral rotations and local polar displacements in WO3/ReO3 superlattices},
author = {Joseph T. Schick and Lai Jiang and Diomedes Saldana-Greco and Andrew M. Rappe},
journal= {arXiv preprint arXiv:1405.3699},
year = {2014}
}