Possibility of the non-phonon mechanism of superconductivity in a layered Fermi liquid

Abstract

Superconductivity and the metal-insulator (MI) phase transition in a layered two-dimensional (2D) electron liquid, taking into account 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 electron-hole excitations in a layered 2D correlated Fermi liquid can induce the MI phase transition. The possibility of superconductivity mediated by the electron-hole excitations in the case of the dynamical suppression of the vertex correction by the high-frequency plasma excitations is discussed. The dependence of the transition temperature T c on the carrier (doping) density, the interlayer spacing and the dielectric constant is obtained. It is also found that the superconductivity transition temperature at the strong coupling can be given by T c∼ n s/ m ∗ while it is given by a BCS-like formula T c∼1.13 ω c exp (-1/λ eff) at the weak coupling.