From VO 2 to V 2 O 3 : The metal-insulator transition of the Magnéli phase V 6 O 11

The metal-insulator transition (MIT) of V 6 O 11 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 occurring simultaneously. The analysis is based on a unified point of view of the crystal structures of V 6 O 11 , VO 2 , and V 2 O 3 . This allows to group the electronic bands into states behaving similarly to the dioxide or the sesquioxide. While the sesquioxide-like V 3 d yz states show rather weak changes on entering the low-temperature structure, some of the dioxide-like V 3 d x 2 − y 2 states display splittings and shifts similar to those known from VO 2 . The MIT of V 6 O 11 arises as a combination of changes appearing in both of these compounds. Our results shed new light onto the role of particular electronic states for the MIT of V 2 O 3 .