Coulomb pseudopotential, screening and superconductivity in C60.

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.

Physical Review Letters, 69 957-60, 1992.

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