The metalinsulator transition of the Magnéli phase V_{4}O_{7}: Implications for V_{2}O_{3}
Abstract
The metalinsulator transition (MIT) of the Magnéli phase V_{4}O_{7} is studied by means of electronicstructure calculations using the augmented spherical wave method. The calculations are based on the densityfunctional theory and the local density approximation. Changes of the electronic structure at the MIT are discussed in relation to the structural transformations occurring simultaneously. The analysis is based on a unified point of view of the crystal structures of all Magnéli phase compounds V_{n}O_{2n  1} (3 <= n <= 9) as well as of VO_{2} and V_{2}O_{3}. This allows to group the electronic bands into states behaving similarly 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_{4}O_{7}, a strong influence of metalmetal bonding across octahedral faces is found for states both parallel and perpendicular to the hexagonal c_{hex}axis of V_{2}O_{3}. Furthermore, the structural changes at the MIT cause localization of those states, which mediate inplane metalmetal 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_{2}O_{3}.
 Publication:

EPL (Europhysics Letters)
 Pub Date:
 December 2003
 DOI:
 10.1209/epl/i2003002802
 arXiv:
 arXiv:condmat/0309483
 Bibcode:
 2003EL.....64..682S
 Keywords:

 71.20.b;
 71.27.+a;
 71.30.+h;
 Electron density of states and band structure of crystalline solids;
 Strongly correlated electron systems;
 heavy fermions;
 Metalinsulator transitions and other electronic transitions;
 Condensed Matter
 EPrint:
 7 pages, 3 figures, more information at http://www.physik.uniaugsburg.de/~eyert/