Chemical bonding and many-body effects in site-specific x-ray photoelectron spectra of corundum V2O3

Site-specific x-ray photoelectron spectroscopy together with density functional theory calculations based on the local density approximation have identified the chemical bonding, single-particle matrix element, and many-body effects in the x-ray photoelectron spectrum of corundum V2O3. Significant covalent bonding in both the upper and lower lobes of the photoelectron spectrum is found, despite the localized nature of the V 3d electrons that are responsible for the Mott behavior. We show that the approximate treatment of correlation dominates the discrepancy between theory and experiment in the near-Fermi-edge region and that many-body effects of the photoemission process can be modeled by Doniach-Sunjic [J. Phys. C 3, 285 (1970)] asymmetric loss. Correlation effects govern the relative intensity and energy position of the higher level electron bands, and many-body effects dominate the tail region of both the upper and lower lobes of the photoemission spectrum.