Charge ordering in the spinels AlV$_2$O$_4$ and LiV$_2$O$_4$

Y. Z. Zhang; P. Fulde; P. Thalmeier; A. Yaresko

doi:10.1143/JPSJ.74.2153

paper

Charge ordering in the spinels AlV $_{2}$ O $_{4}$ and LiV $_{2}$ O $_{4}$

arXiv:cond-mat/0501408 · doi:10.1143/JPSJ.74.2153

Abstract

We develop a microscopic theory for the charge ordering (CO) transitions in the spinels AlV $_{2}$ O $_{4}$ and LiV $_{2}$ O $_{4}$ (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 KagomÃ© 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 AlV $_{2}$ O $_{4}$ should remain metallic while LiV $_{2}$ O $_{4}$ under pressure should become a semiconductor when charge disproportionation sets in.

Charge ordering in the spinels AlV2​O4​ and LiV2​O4​

Abstract

Charge ordering in the spinels AlV $_{2}$ O $_{4}$ and LiV $_{2}$ O $_{4}$