Superconductivity in hole-doped C60 from electronic correlations

摘要

We derive a model for the highest occupied molecular orbital band of a C60crystal which includes on-site electron-electron interactions. The form of theinteractions are based on the icosahedral symmetry of the C60 molecule togetherwith a perturbative treatment of an isolated C60 molecule. Using this model wedo a mean-field calculation in two dimensions on the [100] surface of thecrystal. Due to the multi-band nature we find that electron-electroninteractions can have a profound effect on the density of states as a functionof doping. The doping dependence of the transition temperature can then bequalitatively different from that expected from simple BCS theory based on thedensity of states from band structure calculations.