Self-consistent study of Anderson localization in the Anderson-Hubbard model in two and three dimensions
We consider the change in electron localization due to the presence of electron-electron repulsion in the \HA model. Taking into account local Mott-Hubbard physics and static screening of the disorder potential, the system is mapped onto an effective single-particle Anderson model, which is studied within the self-consistent theory of electron localization. We find rich nonmonotonic behavior of the localization length $ξ$ in two-dimensional systems, including an interaction-induced exponential enhancement of $ξ$ for small and intermediate disorders although $ξ$ remains finite. In three dimensions we identify for half filling a Mott-Hubbard-assisted Anderson localized phase existing between the metallic and the Mott-Hubbard-gapped phases. For small $U$ there is re-entrant behavior from the Anderson localized phase to the metallic phase.