Chemical disorder induced electronic orders in correlated metals

TL;DR

This paper proposes that chemical disorder can induce electronic magnetic, orbital, or charge order in correlated metals by disrupting quantum fluctuations, with demonstrated results using a spin-fermion model.

Contribution

It introduces a novel mechanism where chemical disorder restores electronic order in correlated metals with local moments and itinerant carriers.

Findings

Disorder can re-establish magnetic order in correlated metals.

Enhanced disorder shortens phase coherence length of carriers.

The mechanism is applicable to various strongly correlated systems.

Abstract

In strongly correlated metals, long-range magnetic order is sometimes found only upon introduction of a minute amount of $disordered$ non-magnetic impurities to the unordered clean samples. To explain such anti-intuitive behavior, we propose a scenario of inducing electronic (magnetic, orbital, or charge) order via chemical disorder in systems with coexisting local moments and itinerant carriers. By disrupting the damaging long-range quantum fluctuation originating from the itinerant carriers, the electronic order preferred by the local moment can be re-established. We demonstrate this mechanism using a realistic spin-fermion model and show that the magnetic order can indeed be recovered as a result of enhanced disorder once the length scale of phase coherence of the itinerant carriers becomes shorter than a critical value. The proposed simple idea has a general applicability to strongly correlated metals, and it showcases the rich physics resulting from the interplay between mechanisms of multiple length scales.