DISCONTINUOUS METAL-INSULATOR TRANSITIONS OF CORRELATED ELECTRONS AT NONZERO TEMPERATURE - EFFECT OF THE SHAPE OF THE DENSITY OF STATES

We discuss the effect of the shape of the density of states (DOS) on the discontinuous metal-insulator transitions of the Mott-Hubbard type at nonzero temperature, within an approach proposed by us previously [cf. Phys. Rev. Lett. 59, 728 (1987)]. We analyze explicitly the influence of the DOS shape on the critical value U(c) of the transition at temperature T = 0, as well as on the metal-insulator boundary line for T > 0. The role of variations in the DOS that determine the magnitude of the short-range Coulomb interaction, driving the transition, is explained in physical terms.