Auxiliary dynamical mean-field approach for Anderson-Hubbard model with off-diagonal disorder

TL;DR

This paper introduces an advanced theoretical framework combining ACPA-DMFT and DMFT to study the complex effects of both diagonal and off-diagonal disorder in strongly correlated electronic systems, revealing new insights into metal-insulator transitions.

Contribution

The work develops a unified, self-consistent approach integrating ACPA-DMFT with DMFT to analyze off-diagonal disorder effects in the Anderson-Hubbard model.

Findings

Off-diagonal disorder significantly affects Mott transitions.

Identification of reentrant metal-insulator transition phenomena.

Demonstration of the method's efficiency in complex disordered systems.

Abstract

This work reports a theoretical framework that combines the auxiliary coherent potential approximation (ACPA-DMFT) with dynamical mean-field theory to study strongly correlated and disordered electronic systems with both diagonal and off-diagonal disorders. In this method, by introducing an auxiliary coupling space with extended local degree of freedom,the diagonal and off-diagonal disorders are treated in a unified and self-consistent framework of coherent potential approximation, within which the dynamical mean-field theory is naturally combined to handle the strongly correlated Anderson-Hubbard model. By using this approach, we compute matsubara Green's functions for a simple cubic lattice at finite temperatures and derive impurity spectral functions through the maximum entropy method. Our results reveal the critical influence of off-diagonal disorder on Mott-type metal-insulator transitions. Specifically, a reentrant phenomenon is identified, where the system transitions between insulating and metallic states under varying interaction strengths. The ACPA-DMFT method provides an efficient and robust computational method for exploring the intricate interplay of disorder and strong correlations.