Mott-Hubbard metal-insulator transition at noninteger filling

Krzysztof Byczuk, Walter Hofstetter, Dieter Vollhardt
2004 Physical Review B  
Correlated electrons in a binary alloy A_xB_1-x are investigated within the Hubbard model and dynamical mean--field theory (DMFT). The random energies ϵ_i have a bimodal probability distribution and an energy separation Δ . We solve the DMFT equations by the numerical renormalization group method at zero temperature, and calculate the spectral density as a function of disorder strength Δ and interaction U at different fillings. For filling factors ν =x or 1+x the lower or upper alloy subband is
more » ... er alloy subband is half filled and the system becomes a Mott insulator at strong interactions, with a correlation gap at the Fermi level. At the metal--insulator transition hysteresis is observed. We also analyze the effective theory in the Δ→∞ limit and find good agreement between analytical and numerical results for the critical interaction U_c at which the metal--insulator transition occurs.
doi:10.1103/physrevb.69.045112 fatcat:zbg6ub5igzfcxbrt3fgokvkbia