A model of superconductivity in alkali-metal-carbon compounds

Abstract

An empirical formula for Tc is suggested for the alkali-metal-doped fulleride superconductors. The increase of Tc with the size of the dopant alkali atoms and the decrease of Tc with the external pressure are well-explained by the proposed formula. It is argued that large optical polarons and bipolarons are the natural quasi-particles of these systems in the normal phase and the superconductivity is induced by either the dynamical pairing of the polarons or the Bose-Einstein condensation of the singlet bipolarons. © 1992.