Charge ordering in the spinels AlV$_2$O$_4$ and LiV$_2$O$_4$
Abstract
We develop a microscopic theory for the charge ordering (CO) transitions in the spinels AlVO and LiVO (under pressure). The high degeneracy of CO states is lifted by a coupling to the rhombohedral lattice deformations which favors transition to a CO state with inequivalent V(1) and V(2) sites forming Kagom\'e and trigonal planes respectively. We construct an extended Hubbard type model including a deformation potential which is treated in unrestricted Hartree Fock approximation and describes correctly the observed first-order CO transition. We also discuss the influence of associated orbital order. Furthermore we suggest that due to different band fillings AlVO should remain metallic while LiVO under pressure should become a semiconductor when charge disproportionation sets in.
Cite
@article{arxiv.cond-mat/0501408,
title = {Charge ordering in the spinels AlV$_2$O$_4$ and LiV$_2$O$_4$},
author = {Y. Z. Zhang and P. Fulde and P. Thalmeier and A. Yaresko},
journal= {arXiv preprint arXiv:cond-mat/0501408},
year = {2007}
}