Derivation of a one-band Hubbard model for CuO planar materials

Abstract

We have performed numerical studies of multiband Hubbard models for the Cu-O planes of the high-${\mathit{T}}_{\mathit{c}}$ materials. For the range of realistic parameters, all low-energy (\ensuremath{\le}2 eV) charge and spin excitations are described by the single-band (possibly extended) Hubbard model with U\ensuremath{\simeq}W, where W is the bandwidth.