Critical Behaviour near the Mott Metal—Insulator Transition in a Two-Band Hubbard Model

Abstract

The Mott metal-insulator transition in the two-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The discontinuity in the chemical potential for the change from hole to electron doping is calculated analytically as a function of the on-site Coulomb interaction U at the d-orbital and the charge-transfer energy Δ between the d- and p-orbitals. Critical behaviour of the quasiparticle weight is also obtained analytically as a function of U and Δ. The analytic results are in good agreement with the numerical results of the exact diagonalization method.