INTERPLAY OF MOTT TRANSITION AND FERROMAGNETISM IN THE ORBITALLY DEGENERATE HUBBARD-MODEL

A slave-boson representation for the degenerate Hubbard model is intro duced. The location of the metal-to-insulator transition that occurs a t commensurate densities is shown to depend weakly on the band degener acy M. The relative weights of the Hubbard subbands depend strongly on M, as well as the magnetic properties. It is also shown that a sizabl e Hund's rule coupling is required in order to have a ferromagnetic in stability appearing. The metal-to-insulator transition driven by an in crease in temperature is a strong function of it.