Evolution of the spectral function in Mott-Hubbard systems with d1 configuration.

Abstract

We have studied the photoemission spectra of perovskite-type Ti 3+ and V 4+ oxides, which have formally the d 1 configuration ranging from a Mott insulator to a paramagnetic metal. The results indicate that as the Mott-Hubbard gap closes, spectral weight is transferred from the upper and lower Hubbard bands to the region near the Fermi level with decreasing U/W (U, d-d Coulomb repulsion energy; W, one-electron d-band width), i.e., from the incoherent to the coherent part of the single-particle spectral function