Octahedral Tilt Instability of ReO_3-type Crystals
Abstract
The octahedron tilt transitions of ABX_3 perovskite-structure materials lead to an anti-polar (or antiferroelectric) arrangement of dipoles, with the low temperature structure having six sublattices polarized along various crystallographic directions. It is shown that an important mechanism driving the transition is long range dipole-dipole forces acting on both displacive and induced parts of the anion dipole. This acts in concert with short range repulsion, allowing a gain of electrostatic (Madelung) energy, both dipole-dipole and charge-charge, because the unit cell shrinks when the hard ionic spheres of the rigid octahedron tilt out of linear alignment.
Cite
@article{arxiv.cond-mat/0311014,
title = {Octahedral Tilt Instability of ReO_3-type Crystals},
author = {Philip B. Allen and Yiing-Rei Chen and Santanu Chaudhuri and Clare P. Grey},
journal= {arXiv preprint arXiv:cond-mat/0311014},
year = {2013}
}
Comments
4 page with 3 figures included; new version updates references and clarifies the arguments