THE DEPENDENCE OF THE HOLE SPECTRUM ON SPIN FRUSTRATION AND DIRECT HOPPING IN THE 2-BAND HUBBARD-MODEL

The one-hole spectrum epsilon(k) in the CuO2 plane is studied in the framework of the two-band Hubbard model with direct O-O hopping h. The finite O-hole concentration n is taken into account via the frustration-alpha in the Cu spin subsystem. The epsilon(k) minimum position and Fermi surface topology strongly depend on the alpha- and h-values. The density of states has a sharp peak near the bottom of the band. The model demonstrates the non-rigid-band behaviour of epsilon(k) and Fermi level pinning observed in recent photoemission experiments on high-T(c) superconductors.