Static Screening and Delocalization Effects in the Hubbard-Anderson Model

TL;DR

This paper investigates how electron screening affects localization in a Hubbard-Anderson model, revealing a nonmonotonic relationship between interaction strength and localization length, aligning well with numerical findings.

Contribution

It introduces two static approximation methods to analyze disorder screening effects on electron localization, highlighting a maximum localization length at intermediate interactions.

Findings

Localization length shows nonmonotonic dependence on interaction strength.

Maximum localization length occurs at an intermediate interaction value.

Approach agrees with recent numerical results.

Abstract

We study the suppression of electron localization due to the screening of disorder in a Hubbard-Anderson model. We focus on the change of the electron localization length at the Fermi level within a static picture, where interactions are absorbed into the redefinition of the random on-site energies. Two different approximations are presented, either one yielding a nonmonotonic dependence of the localization length on the interaction strength, with a pronounced maximum at an intermediate interaction strength. In spite of its simplicity, our approach is in good agreement with recent numerical results.