Density functional calculations of electronic structure and magnetic properties of the hydrocarbon K(3)picene superconductor near the metal-insulator transition

Abstract

We have investigated the electronic structures and magnetic properties of a newly discovered hydrocarbon superconductor, K(3)picene, having T-c = 18 K. We have shown that the metal-insulator transition is driven in K(3)picene by 5% volume enhancement with the formation of the local magnetic moment. Active bands for the superconductivity near the Fermi level ( E-F) have hybridized character of LUMO and LUMO+1 of the picene molecule. Fermi surfaces of K(3)picene manifest neither prominent nesting feature nor marked two-dimensional behavior. By estimating the ratio of the Coulomb interaction, U, and the bandwidth, W, of the active bands near EF, we have demonstrated that K(3)picene is located in the vicinity of the Mott transition. Our findings suggest that K(3)picene is a strongly correlated electron system.