A MODEL FOR ELECTRON CORRELATIONS IN HYBRID BANDS

We consider the correlated motion of electrons in a conduction band hybridizing with completely localized non-degenerate atomic levels. Only intra-atomic Coulomb repulsion is included. In the limit of large Coulomb repulsion the quasi-particle bands are those of the non-interacting electrons but with hybridization matrix elements reduced by excluding atomic sites occupied by other electrons of opposite spin. Self-consistent solutions giving a ferromagnetic ground state exist if the hybridization is sufficiently large, the number of conduction band states lying below the atomic energy level T 0 is small and the Fermi level lies just below T0. If the Fermi level lies above T0 the ground state is non-magnetic. In the ferromagnetic state the spin polarization of the conduction band is always parallel to the localized d moments. Possible implications for the ferromagnetism of the transition metals are discussed.