Multi-Orbital Hubbard model in infinite dimensions: Quantum Monte Carlo calculation

J. E. Han(1,2), M. Jarrel(3) and D.L. Cox(1,4)
(1) Department of Physics, The Ohio State University, Columbus, Ohio 43210 (2) Max-Planck-Institut für Festkörperforschung, D-70506 Stuttgart, Germany (3) Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221 (4) Department of Physics, University of California, Davis, California 95616

Using Quantum Monte Carlo we compute thermodynamics and spectra for the orbitally degenerate Hubbard model in infinite spatial dimensions. With increasing orbital degeneracy we find in the one-particle spectra: broader Hubbard bands (consistent with increased kinetic energy), a narrowing Mott gap, and increasing quasi-particle spectral weight. In opposition, Hund's rule exchange coupling decreases the critical on-site Coulomb energy for the Mott transition. The metallic regime resistivity for two-fold degeneracy is quadratic-in-temperature at low temperatures.

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