Metal-insulator transition in a weakly interacting disordered electron system

Abstract

The interplay of interactions and disorder is studied using the Anderson-Hubbard model within the typical medium dynamical cluster approximation. Treating the interacting, nonlocal cluster self-energy [Sigma(c)[(g) over tilde](i, j not equal i)] up to second order in the perturbation expansion of interactions, U-2, with a systematic incorporation of nonlocal spatial correlations and diagonal disorder, we explore the initial effects of electron interactions (U) in three dimensions. We find that the critical disorder strength (W-c(U)), required to localize all states, increases with increasing U; implying that the metallic phase is stabilized by interactions. Using our results, we predict a soft pseudogap at the intermediate W close to W-c(U) and demonstrate that the mobility edge (omega(epsilon)) is preserved as long as the chemical potential, mu, is at or beyond the mobility edge energy.