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.