ON THE ELECTRONIC-STRUCTURE OF HIGH-TC SUPERCONDUCTORS - UNDOPED CUO2-PLANE

The value of screened Coulomb repulsion of 3d-copper electrons and 2p-oxygen electrons is calculated. The spectrum of electronic states of the undoped sample is found taking into account the crystal field and hopping effects. Hopping essentially enhanced the splitting of oxygen 2p-orbitals. This splitting gives us the possibility to explain the second oxygen peak observed in photoabsorption by 4-5 eV below the main peak. The electronic structure of the doped sample essentially depends on the existence of this splitting.