Charge-density-wave semimetallic and superconducting states for A3C60.

Abstract

It is shown that the attractive Hubbard model for the face-centered-cubic lattice possesses a charge-density-wave semimetallic phase with a superconducting ground state. The properties of this phase are consisent with the behavior of alkali fullerides. The overlapping bands result in peaks in the density of states and anomalous mid-infrared absorption. The low density of carriers leads to a high normal-state resistivity, a short coherence length and a long penetration depth, as observed. The difference between this and a spin-density-wave semimetallic state, which is predicted to occur in the repulsive Hubbard model, is briefly discussed.