Superconductivity in molecular solids with Jahn-Teller phonons

Abstract

We analyze fulleride superconductivity at experimental doping levels, treating the electron-electron and electron-phonon interactions on an equal footing, and establish the existence of novel physics which helps explain the unusually high superconducting transition temperatures in these systems. The Jahn-Teller phonons create a local (intramolecular) pairing that is surprisingly resistant to the Coulomb repulsion, despite the weakness of retardation in these low-bandwidth systems. The requirement for coherence throughout the solid to establish superconductivity then yields a very strong doping dependence to Tc, one consistent with experiment and much stronger than expected from standard Eliashberg theory.