Correlated electrons in the presence of disorder

TL;DR

This paper explores how electronic correlations and disorder influence material phases, using advanced theoretical models to identify various insulating and metallic states and how disorder can enhance ferromagnetism.

Contribution

It introduces a non-perturbative DMFT approach with typical local density of states to analyze the Anderson-Hubbard model and reveals disorder-induced enhancement of ferromagnetism in the periodic Anderson model.

Findings

Identification of correlated metallic, Mott insulating, and Anderson insulating phases.

Disorder enhances the Curie temperature by increasing local f-moments.

The approach detects the competition between Anderson localization and antiferromagnetism.

Abstract

Several new aspects of the subtle interplay between electronic correlations and disorder are reviewed. First, the dynamical mean-field theory (DMFT)together with the geometrically averaged ("typical") local density of states is employed to compute the ground state phase diagram of the Anderson-Hubbard model at half-filling. This non-perturbative approach is sensitive to Anderson localization on the one-particle level and hence can detect correlated metallic, Mott insulating and Anderson insulating phases and can also describe the competition between Anderson localization and antiferromagnetism. Second, we investigate the effect of binary alloy disorder on ferromagnetism in materials with $f$-electrons described by the periodic Anderson model. A drastic enhancement of the Curie temperature $T_c$ caused by an increase of the local $f$-moments in the presence of disordered conduction electrons is discovered and explained.