Doping dependence of high-energy spectral weights for the high-Tccuprates

Abstract

In this paper we present calculations of the photo- and inverse photoemission spectra, and the O 1s and Cu 2p core-level spectra for the high-${\mathit{T}}_{\mathit{c}}$ materials, using a multiband Hubbard Hamiltonian. The spectra are obtained for small clusters containing two Cu atoms (${\mathrm{Cu}}_2$ ${\mathrm{O}}_7$ and ${\mathrm{Cu}}_2$ ${\mathrm{O}}_8$) for the undoped, electron-doped, and hole-doped cases. In order to investigate the sensitivity of the spectra to cluster size and localized versus delocalized oxygen levels, a comparison is made with a (k-dependent) impurity approach and results from a ${\mathrm{CuO}}_4$ cluster. Special attention is paid to the doping dependence of the spectra and the low-energy states and to the redistribution of spectral weights upon doping.