Plasmon mechanism of high-temperature superconductivity in cuprate metal-oxide compounds

The plasmon mechanism of Cooper pairing of almost-free open-quotes lightclose quotes carriers in a wide 2D band is considered in the framework of standard superconductivity theory in the intermediate-coupling approximation. The model used is that of a layered metal with quasi-two-dimensional electron spectrum and a narrow band near the Fermi level, with exchange of virtual quanta of low-frequency collective excitations of the charge density of almost localized open-quotes heavyclose quotes carriers in a narrow 2d-band (acoustic plasmons), which are hybridized with dipole-active oxygen vibrational mode (optical phonons) in the entire volume of the Brillouin band. It is shown that when account is taken of the multilayer structure of cuprate metal-oxide compounds and of multiparticle Coulomb correlations (of the type of open-quotes local-fieldclose quotes effects), such a mechanism can ensure quite high values of the critical temperature of the superconducting transition temperature Tc and describes correctly all the main properties of high-temperature superconductors, such as the nonmonotonic dependence of Tc on the density of the doping impurity or on the oxygen content, the rise of Tc with increase of the number n of the cuprate CuO2 layers in the primitive cell of the crystal with a tendency to saturation at n ≥ 3, the anomaly of the oxygen isotopic effect, and others. 93 refs., 13 figs