Mott-Hubbard Transition and Anderson Localization: Generalized Dynamical Mean-Field Theory Approach

TL;DR

This paper employs a generalized dynamical mean-field theory approach to analyze the phase diagram of the Anderson-Hubbard model, revealing the interplay of Mott-Hubbard and Anderson transitions, including a disorder-induced Mott insulator to metal transition.

Contribution

It introduces a comprehensive DMFT+ approximation framework to study correlated and disordered systems, combining NRG solutions with localization theory.

Findings

Identification of correlated metal, Mott insulator, and Anderson insulator phases.

Observation of both Mott-Hubbard and Anderson metal-insulator transitions.

Discovery of disorder-induced Mott insulator to metal transition.

Abstract

Density of states, dynamic (optical) conductivity and phase diagram of strongly correlated and strongly disordered paramagnetic Anderson-Hubbard model are analyzed within the generalized dynamical mean field theory (DMFT+\Sigma approximation). Strong correlations are accounted by DMFT, while disorder is taken into account via the appropriate generalization of self-consistent theory of localization. The DMFT effective single impurity problem is solved by numerical renormalization group (NRG) and we consider the three-dimensional system with semi-elliptic density of states. Correlated metal, Mott insulator and correlated Anderson insulator phases are identified via the evolution of density of states and dynamic conductivity, demonstrating both Mott-Hubbard and Anderson metal-insulator transition and allowing the construction of complete zero-temperature phase diagram of Anderson-Hubbard model. Rather unusual is the possibility of disorder induced Mott insulator to metal transition.