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-Tc materials. For the range of realistic parameters, all low-energy (≤2 eV) charge and spin excitations are described by the single-band (possibly extended) Hubbard model with UW, where W is the bandwidth.