CHARGE-TRANSFER METAL-INSULATOR TRANSITIONS IN THE SPIN-1 2 FALICOV-KIMBALL MODEL/

The spin-1/2 Falicov-Kimball model is solved exactly on an infinite-co ordination-number Bethe lattice in the thermodynamic limit. This model is a paradigm for a charge-transfer metal-insulator transition, where the occupancy of localized and delocalized electronic orbitals rapidl y changes at the metal-insulator transition (rather than the character of the electronic states changing from insulating to metallic as in a Mott-Hubbard transition). The exact solution displays both continuous and discontinuous (first-order) transitions. [S0163-1829(98)02419-9].