Disorder Screening in Strongly Correlated Systems

TL;DR

This paper reveals that in strongly correlated systems, electron interactions can enhance disorder screening contrary to weak-coupling expectations, leading to stabilized metallicity.

Contribution

It demonstrates that strong correlations can enhance screening effects despite reduced compressibility, a phenomenon linked to non-perturbative Kondo-like processes.

Findings

Screening is enhanced in strongly correlated regimes.

Metallicity is stabilized when interactions and disorder are comparable.

Weak-coupling theories underestimate screening effects in these systems.

Abstract

Electron-electron interactions generally reduce the low temperature resistivity due to the screening of the impurity potential by the electron gas. In the weak-coupling limit, the magnitude of this screening effect is determined by the thermodynamic compressibility which is proportional to the inverse screening length. We show that when strong correlations are present, although the compressibility is reduced, the screening effect is nevertheless strongly enhanced. This phenomenon is traced to the same non-perturbative Kondo-like processes that lead to strong mass enhancements, but which are absent in weak coupling approaches. We predict metallicity to be strongly stabilized in an intermediate regime where the interactions and the disorder are of comparable magnitude.