Critical behavior at Mott-Anderson transition: a TMT-DMFT perspective

TL;DR

This paper analyzes the critical behavior near the Mott-Anderson transition using TMT-DMFT, revealing a two-fluid behavior where some electrons localize via Mott physics and others via Anderson localization, depending on disorder strength.

Contribution

It introduces an analytical solution within TMT-DMFT that elucidates the dependence of critical behavior on particle-hole symmetry and disorder strength.

Findings

Identification of a two-fluid behavior at strong disorder

Partial Mott localization of electrons

Distinct Anderson localization of remaining electrons

Abstract

We present a detailed analysis of the critical behavior close to the Mott-Anderson transition. Our findings are based on a combination of numerical and analytical results obtained within the framework of Typical-Medium Theory (TMT-DMFT) - the simplest extension of dynamical mean field theory (DMFT) capable of incorporating Anderson localization effects. By making use of previous scaling studies of Anderson impurity models close to the metal-insulator transition, we solve this problem analytically and reveal the dependence of the critical behavior on the particle-hole symmetry. Our main result is that, for sufficiently strong disorder, the Mott-Anderson transition is characterized by a precisely defined two-fluid behavior, in which only a fraction of the electrons undergo a "site selective" Mott localization; the rest become Anderson-localized quasiparticles.