Mott-Hubbard insulators for systems with orbital degeneracy

Olle Gunnarsson (a), Erik Koch (b), and Richard M. Martin (b)
(a) Max-Planck-Institut für Festkörperforschung, Stuttgart
(b) Department of Physics, University of Illinois, Urbana-Champaign

We study how the electron hopping reduces the Mott-Hubbard band gap in the limit of a large Coulomb interaction U and as a function of the orbital degeneracy N. The results support the conclusion that the hopping contribution grows as roughly sqrt{N}W, where W is the one-particle band width, but in certain models a crossover to a ~NW behavior is found for sufficiently large N.

Physical Review B 56 , 1146 (1997).

A postscript file is available at this http URL

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