Importance of the V 3d-O 2p hybridization in the Mott-Hubbard material V2O3

We studied the changes in the electronic structure of V2O3 using a cluster model. The calculations included fluctuations from the coherent band in the metallic phase and nonlocal Mott-Hubbard fluctuations in the insulating phase. The incoherent structure is mostly related to the usual ligand screening channel (3d(2)L(_)). The coherent peak in the metallic phase corresponds to coherent band fluctuations (3d(2)C(_)). However, The Mott-Hubbard screened state in the insulating phase (3d(2)D(_)) appears at higher energies. The transfer of spectral weight from the 3d(2)L(_) to the 3d(2)D(_) state produces the opening of the band gap. The photon energy dependence of the spectra is partly related to the relative V 3d-O 2p cross sections. The calculations reproduce also the experimental changes observed in the V 1s core-level spectra. The above results suggest that the Mott-Hubbard transition in V2O3 requires a multiband model.