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 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.

References in corpus (5)

• Long Range Charge Ordering in Magnetite Below the Verwey Transition
• Charge and orbital order in Fe_3O_4
• Orbital and magnetic transitions in geometrically-frustrated vanadium spinels -- Monte Carlo study of an effective spin-orbital-lattice coupled model --
• Spin-Orbital Fluctuations and a large mass enhancement in LiV_2O_4
• Metal-to-Insulator Transition, Spin Gap Generation, and Charge Ordering in Geometrically Frustrated Electron Systems

Cited by in corpus (1)

• Can the Mott Insulator TiOCl be Metallized by Doping? A First-Principles Study