Authors: R. Bulla, T.A. Costi, and D. Vollhardt
Journal:
Phys. Rev. B 64, 045103 (2001)
Wilson's numerical renormalization group (NRG) method for the calculation of dynamic properties of impurity models is generalized to investigate the effective impurity model of the dynamical mean field theory at finite temperatures. We calculate the spectral function and self-energy for the Hubbard model on a Bethe lattice with infinite coordination number directly on the real frequency axis and investigate the phase diagram for the Mott-Hubbard metal-insulator transition. While for T less than T_c approx 0.02W (W: bandwidth) we find hysteresis with first-order transitions both at U_c1 (defining the insulator to metal transition) and at U_c2 (defining the metal to insulator transition), at T greater than T_c there is a smooth crossover from metallic-like to insulating-like solutions.