DETERMINATION OF THE MIXING POTENTIAL-V BETWEEN THE BIPOLARON AND THEITINERANT-ELECTRON AND POSSIBLE 2-COMPONENT INTERACTION SUPERCONDUCTIVITY BASED ON A LOW N(E-F) FOR DOPED FULLERENES

A mixing potential V=0.23 eV was obtained in the normal state within t he negative U Anderson-lattice model (two-component model) if the addi tional spectral weight in the band gap observed on K3C60 is attributed to the additional bipolaron state. The superconducting transition tem perature T-c, penetration depth lambda, coherent length xi, thermodyna mic critical field H-c, specific heat jump Delta C/T-c and isotope eff ect exponent cu can be well reproduced within the same model based on a low density of states at the Fermi level, N(E-F)approximate to 3 sta tes/eV C-60 spin, which is another general observation when using phot oemission spectroscopy, with a mixing potential V=0.075-0.12 eV. The s maller discrepancy in V seems to support the two-component interaction superconductivity for doped fullerenes. (C) 1997 Elsevier Science B.V .