Novel spectralevolution with electron doping in d⁰ transition metal oxides

Abstract

We discuss high-energy spectroscopic results for systems representing electron doping near the d⁰ configuration and establish that the spectral evolution with doping is inconsistent with expectations based on the Hubbard model. We argue that this failure arises due to the neglect of disorder in the real system. We present a new theoretical approach which takes into account the inhomogeneity of real systems; this approach provides results which are qualitatively different from the standard homogeneous models, but are in agreement with the experimental observations.