ON THE THEORY OF HIGH-TEMPERATURE SUPERCONDUCTIVITY

The construction of a theory of the superconductivity of oxide metals based on the polar model is discussed. The matrix electron Green's fun ction is calculated with allowance for both the electron-phonon intera ction and strong Coulomb correlations. The possible raising of T(c) du e to the lattice instability associated with strong anharmonicity of t he oxygen ion vibrations in perovskite-like compounds is considered. S trong electron correlations are taken into account in a one-band t-J m odel. Because of a local restriction that precludes doubly occupied st ates in a system with strong correlation, only d-wave pairing is possi ble.