Interplay of Mott transition and ferromagnetism in the orbitally degenerate Hubbard model

A slave-boson representation for the degenerate Hubbard model is introduced. The location of the metal-to-insulator transition that occurs at commensurate densities is shown to depend weakly on the band degeneracy M. The relative weights of the Hubbard subbands depend strongly on M, as well as the magnetic properties. It is also shown that a sizable Hund's rule coupling is required in order to have a ferromagnetic instability appearing. The metal-to-insulator transition driven by an increase in temperature is a strong function of it.