Mott transition in the multi-band Hubbard model in infinite dimensions

Abstract

The Mott metal–insulator transition in the multi-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The critical interaction U c is obtained analytically. For the symmetric case and for orbital degeneracy M we find U c =(4M+2) L 2 where L 2 is the second moment of the non-interacting density of states. We also derive an analytical expression for the discontinuity of the chemical potential μ( n) at the filling n= M for U> U c. The findings are in good agreement with numerical results obtained from the exact diagonalization method.