Similarities in the screening effects of the core level and valence band spectra ofV O2

Abstract

We calculated the core level and valence band spectra ofV O2 using an extended cluster model. The distribution of spectral weight is similar in both corelevel and valence band spectra and is related to the different screening mechanisms.Namely, the low energy structures in the spectra correspond to well screened final states,whereas the poorly screened final states appear at higher energies. The latter producethe charge transfer satellite observed in the core level spectra, and are relatedto the resonance in the constant initial state spectra of the valence band. Thechanges in the spectral weight across the metal–insulator transition are due tothe different non-local screening channels present in each phase, and are alsosimilar in both core level and valence band spectra. The calculation also shows arelatively large O 2p contribution in both spectra, which, in turn, helps to explain theenhancement of the coherent feature at higher photon energies. This suggeststhat the incoherent peak cannot be solely attributed to the lower Hubbard band.