Dual Fermion Method for Disordered Electronic Systems

TL;DR

This paper extends the dual fermion approach to disordered electronic systems, capturing non-local correlations and weak localization effects, providing an alternative to cluster CPA methods.

Contribution

The authors develop a dual fermion method for disordered systems using the replica approach, enhancing the CPA by including non-local correlations and localization effects.

Findings

Good agreement with cluster CPA extensions

Captures weak localization effects

Applicable to disordered interacting systems

Abstract

While the coherent potential approximation (CPA) is the prevalent method for the study of disordered electronic systems, it fails to capture non-local correlations and Anderson localization. To incorporate such effects, we extend the dual fermion approach to disordered non-interacting systems using the replica method. Results for single- and two- particle quantities show good agreement with cluster extensions of the CPA; moreover, weak localization is captured. As a natural extension of the CPA, our method presents an alternative to the existing cluster theories. It can be used in various applications, including the study of disordered interacting systems, or for the description of non-local effects in electronic structure calculations.