Nonphonon mechanism of high-temperature superconductivity in cuprates

Superconductivity and the metal-insulator phase transition in a layered two-dimensional (2D) electron liquid, taking into account electron-electron correlation effects and spin density fluctuations, have been considered by means of the Fermi-liquid approach. It is shown that the electron-electron interaction mediated by the virtual charge density excitations in a layered 2D correlated Fermi liquid has the short-range attractive character at the intermediate electron density. It is found that such interaction leads to both superconductivity at the intermediate density of carriers and the phase transition to the insulating state with the decrease of the density. The dependence of transition temperature Tc on the doping density, interlayer spacing and dielectric constant of the cuprate under investigation is also shown. A optimum Tc for a single-layer cuprate and the possibility to reach room temperature superconductivity are predicted as well. This indicates a direction to synthesize the compounds with superconductivity at higher temperature