THEORETICAL INTERPRETATION OF VALENCE BAND PHOTOEMISSION SPECTRA IN YBA2CU3O7

Angle resolved one-hole spectra have been calculated starting from a realistic tight-binding Hamiltonian and including correlation and surface effects. The hole self-energy has been evaluated using the t-matrix approximation for the hole-hole scattering. To account for surface effects the local density of states of the outermost atomic layers has been determined assuming an ideal termination of the crystal and a non polar basal plane surface. The theoretical curves allow one to assign the main features of the spectra at high symmetry points of the Brillouin zone, except for the peak observed at 8.5 eV binding energy. It is suggested that the discrepency may arise from the neglecting of the k-dependence in the self-energy or from the extrinsic nature of the peak. © 1990.