Discontinuous metal-insulator transitions and Fermi-liquid behavior of correlated electrons

A simple thermodynamic theory is given of the metal-insulator transitions concurrent with a localization of electrons in a half-filled correlated band. The approach supplies a complete phase diagram for the system (${\mathrm{V}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Cr}}_{\mathrm{x}}$ ${)}_2$ ${\mathrm{O}}_3$. We show also that for an almost half-filled band the disappearance of local moments is accompanied by a transition to a heavy Fermi liquid.