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

Y. Z. Zhang·P. Fulde·P. Thalmeier·A. Yaresko
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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 Kagomé 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.

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Y. Z. Zhang, P. Fulde, P. Thalmeier, A. Yaresko. 2005-01-18. Charge ordering in the spinels AlV$_2$O$_4$ and LiV$_2$O$_4$. https://doi.org/10.1143/jpsj.74.2153

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