Gunnarsson O., Zwichnagl G.
The authors estimate the Coulomb pseudopotential mu * for a model of undoped C60, renormalizing away all subbands but the t1 mu conduction band by summing ladder diagrams in the screened interaction. The renormalization of mu * is small. For doped C60 the screened U is calculated. A very efficient metallic screening is found for the intraband U, but not for the interband U, suggesting a large renormalization of mu * within a ladder diagram approach. Exact results for a two-band model suggest, however, that the ladder diagrams strongly overestimate the renormalization.
Max-Planck Institut für Festkörperforschung; Postfach 80 06 65 D-70506 Stuttgart |