Slave-Boson Functional-Integral Approach to the Hubbard Model with Orbital Degeneracy

Abstract

A slave-boson functional-integral method has been developed for the Hubbard model with arbitrary, orbital degeneracy $D$. Its saddle-point mean-field theory is equivalent to the Gutzwiller approximation, as in the case of single-band Hubbard model. Our theory is applied to the doubly degenerate ($D=2$) model, and numerical calculations have been performed for this model in the paramagnetic states. The effect of the exchange interaction on the metal-insulator (MI) transition is discussed. The critical interaction for the MI transition is analytically calculated as functions of orbital degeneracy and electron occupancy.

Latex 20 pages, 9 figures available on request to [email protected] Note: published in J. Physical Society of Japan with some minor modifications

References in corpus (2)

• Metal-Insulator Transitions in Degenerate Hubbard Models and A${}_x$C${}_{60}$
• Theory on the Itinerant Ferromagnetism in the $3d$-transition metal systems

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