Importance of interorbital charge transfers for the metal-to-insulator transition of BaVS3

The underlying mechanism of the metal-to-insulator transition (MIT) in BaVS3 is investigated, using dynamical mean-field theory in combination with density functional theory. It is shown that correlation effects are responsible for a strong charge redistribution, which lowers the occupancy of the broader A(1g) band in favor of the narrower E(g) bands and thereby substantially modifies the Fermi surface. This resolves several discrepancies between band theory and the experimental findings, such as the observed value of the charge-density-wave ordering vector associated with the MIT, and the presence of local moments in the metallic phase.