The Metal-Insulator Transition of the Magneli phase V_4O_7: Implications for V_2O_3

Abstract

The metal-insulator transition (MIT) of the Magneli phase V_4O_7 is studied by means of electronic structure calculations using the augmented spherical wave method. The calculations are based on density functional theory and the local density approximation. Changes of the electronic structure at the MIT are discussed in relation to the structural transformations occuring simultaneously. The analysis is based on a unified point of view of the crystal structures of all Magneli phase compounds V_nO_2n-1 (3 =< n =< 9) as well as of VO_2 and V_2O_3. This allows to group the electronic bands into states behaving similar to the dioxide or the sesquioxide. In addition, the relationship between the structural and electronic properties near the MIT of these oxides can be studied on an equal footing. For V_4O_7, a strong influence of metal-metal bonding across octahedral faces is found for states both parallel and perpendicular to the hexagonal c_hex axis of V_2O_3. Furthermore, the structural changes at the MIT cause localization of those states, which mediate in-plane metal-metal bonding via octahedral edges. This band narrowing opens the way to an increased influence of electronic correlations, which are regarded as playing a key role for the MIT of V_2O_3.

arXiv comment7 pages, 3 figures, more information at http://www.physik.uni-augsburg.de/~eyert/

References in corpus (6)

• The metal-insulator transitions of VO2: A band theoretical approach
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• Orbital occupation, local spin and exchange interactions in V2O3
• The Metal-Insulator Transition of NbO2: an Embedded Peierls Instability
• From VO2 to V2O3: The Metal-Insulator Transition of the Magneli Phase V6O11
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Cited by in corpus (8)

• Charge order and spin-singlet pairs formation in Ti4O7
• Charge order, orbital order, and electron localization in the Magneli phase Ti4O7
• Covalent bonding and hybridization effects in the corundum-type transition-metal oxides V2O3 and Ti2O3
• Electronic structure of V${}_4$O${}_7$: charge ordering, metal-insulator transition and magnetism
• Optical conductivity of V4O7 across its metal-insulator transition
• Electronic structure of the zigzag spin-chain compound In${}_2$VO${}_5$
• Substrate effects on V2O3 thin films
• Influence of the vacuum interface on the charge distribution in V2O3 thin films