HUBBARD MODELS WITH RANDOM HOPPING IN D = INFINITY

A class of Hubbard models with random hopping is examined as models of strongly correlated electrons in disordered systems. In the limit of large spatial dimensionality the problem is reduced to solving an ensemble of self-consistently determined Anderson impurity models. Even at intermediate correlation, disorder-induced local moment formation occurs, leading to a diverging specific heat coefficient inside the metallic phase. For stronger correlation, the system undergoes a metal-insulator transition where the dc conductivity abruptly drops to zero, displaying minimum metallic conductivity.