Max-Planck-Institut für Festkörperforschung, Stuttgart;
Department of Physics, University of Illinois, Urbana, Illinois 6180;
Department of Theoretical Physics, University of Lund, S-223 62 Lund, Sweden
We study the condition for a Mott-Hubbard metal-insulator transition. We find that the orbital degeneracy N shifts the critical value of the Coulomb interaction where the transition takes place by a factor of the order of square root N. This explains why A3C60 (A=K, Rb) are metals. We furthermore calculate the Pauli susceptibility chi . From the calculated many-body enhancement and experimental values of chi , we deduce the density of states. Finally, we discuss the strength of the electron-phonon interaction and the superconductivity.
Electrochemical Society Proceedings 97-14, 1040-1054.
Max-Planck Institut für Festkörperforschung;
Postfach 80 06 65 D-70506 Stuttgart
