MECHANISMS OF SUPERCONDUCTING PHASE-TRANSITION IN MOLECULAR-SOLIDS - THE CASE OF DOPED FULLERENES

The surprising discovery of superconductivity at high temperature in d oped fullerenes (C60: icosahedral hollow cluster balls of 60 carbon at oms) has posed another challenge regarding the possible mechanisms of superconducting phase transitions in such molecular systems. In the pr esent communication, the molecular, crystal and electronic structure o f the fullerenes have been discussed and the mechanism of superconduct ivity in alkali doped fullerides MxC60(M = K, Rb, Cs, Tc etc) is devel oped. The mechanism comprises a combination of phonon and high energy electronic boson exchange as in the case of cuprates. The electronic b oson process involves bond polarization in interaction with conduction electrons. The theory accounts for the high transition temperature (T (c)) observed in these systems. Further, predictions based on this mec hanism are consistent with the observed isotope effect and the superco nducting energy gap in M3C60 fullerides.