Max-Planck-Inst. Festkoerperforschung, Stuttgart, D-70506, Germany
The Mott-Hubbard transition is studied for a Hubbard model with orbital
degeneracy N, using a diffusion Monte Carlo method. Based on general arguments,
the authors conjecture that the Mott-Hubbard transition takes place for
U/W .apprx. .sqroot.N, where U is the Coulomb interaction and W is the
bandwidth. This is supported by exact-diagonalization and Monte Carlo calcns.
Realistic parameters for the doped fullerenes lead to the conclusions that
stoichiometric A3C60 (A = K, Rb) are near the Mott-Hubbard transition,
in a correlated metallic state.
Physical Review B, 54 R11026-R11029, 1996.
Max-Planck Institut für Festkörperforschung;
Postfach 80 06 65 D-70506 Stuttgart
