Electronic structure of V${}_4$O${}_7$: charge ordering, metal-insulator transition and magnetism

Abstract

The low and high-temperature phases of V${}_4$O${}_7$ have been studied by \textit{ab initio} calculations. At high temperature, all V atoms are electronically equivalent and the material is metallic. Charge and orbital ordering, associated with the distortions in the V pseudo-rutile chains, occur below the metal-insulator transition. Orbital ordering in the low-temperature phase, different in V${}^{3+}$ and V${}^{4+}$ chains, allows to explain the distortion pattern in the insulating phase of V${}_4$O${}_7$. The in-chain magnetic couplings in the low-temperature phase turn out to be antiferromagnetic, but very different in the various V${}^{4+}$ and V${}^{3+}$ bonds. The V${}^{4+}$ dimers formed below the transition temperature form spin singlets, but V${}^{3+}$ ions, despite dimerization, apparently participate in magnetic ordering.

10 pages, 6 figures, 2 tables

References in corpus (6)

• Orbital-assisted metal-insulator transition in VO${}_2$
• Anisotropy and Magnetism in the LSDA+U Method
• Quantum confinement of Mott electrons in ultrathin LaNiO3/LaAlO3 superlattice
• Enhanced Pressure Dependence of Magnetic Exchange in A2+[V2]O4 Spinels Approaching the Itinerant Electron Limit
• Homopolar bond formation in ZnV${}_2$O${}_4$ close to a metal-insulator transition
• Relationship between orbital structure and lattice distortions: CE phase of manganites, revisited

Cited by in corpus (5)

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• Electronic and magnetic properties of the Ti${}_5$O${}_9$ Magnéli phase
• Charge States of Ions, and Mechanisms of Charge-Ordering Transitions
• Optical conductivity of V4O7 across its metal-insulator transition