Electronic Structure of Vanadium Dioxide: Ab initio Density Functional Theory Studies of Periodic and Local Systems

Abstract

The electronic structure of vanadium dioxide in its monoclinic and tetragonal (rutile) phase are calculated using the ab initio FP-LAPW method. Both VO2 phases yield very similar band structures and densities of states (DOS) as expected from their structural similarity. A comparison of theoretical band dispersions of tetragonal VO2 with recent angular resolved photoemission data yields very good agreement, which confirms the reliability of the FP-LAPW method to account for electronic dispersions in the present systems. The calculations yield metallic behavior for both VO2 phases in contrast to experimental findings of the monoclinic phase being a small gap semiconductor. This discrepancy is explained by missing correlation contributions in the density functional theory (DFT) scheme used in the calculations. The DOS curves of the bulk systems are compared with the DOS of VO2(011) surface clusters obtained by DFT calculations and yield very close similarity in the O 2p band region without surface specific features which remains to be explained.