High-temperature superconductivity and normal state in the Holstein-t-J model

A possible origin of the high-temperature superconductivity in cuprates has been suggested. It is supposed that electron-phonon interaction determines the strong correlation narrowing of the electron band. It provides the conditions for the formation of a singlet electron pair coupled by exchange interaction. For the pure t-J model it has been proved that these electron pairs are destroyed by a strong effective kinematic field. The detailed analysis of an influence of the Holstein polaron excitations upon normal and superconducting properties of the strongly correlated electrons was made. A calculated critical temperature of the superconductivity and gap function are in good agreement with experimental data for cuprates.