Emergence of quasi-metallic state in disordered 2D electron gas due to strong interactions

TL;DR

This paper investigates how strong electron-electron interactions in disordered 2D electron gases lead to a quasi-metallic state by suppressing localization effects, with implications for diffusion and conductivity corrections.

Contribution

It demonstrates that strong interactions modify diffusion and suppress localization, revealing a quasi-metallic phase in disordered 2D electron systems beyond weak coupling theories.

Findings

Strong repulsion reduces the density of states at the Fermi level.

Weak localization becomes unobservable at accessible temperatures.

Diffusion is significantly altered due to an effective Higgs-like mechanism.

Abstract

The interrelation between disorder and interactions in two dimensional electron liquid is studied beyond weak coupling perturbation theory. Strong repulsion significantly reduces the electronic density of states on the Fermi level. This makes the electron liquid more rigid and strongly suppresses elastic scattering off impurities. As a result the weak localization, although ultimately present at zero temperature and infinite sample size, is unobservable at experimentally accessible temperature at high enough densities. Therefore practically there exists a well defined metallic state. We study diffusion of electrons in this state and find that the diffusion pole is significantly modified due to "mixture" with static photons similar to the Anderson - Higgs mechanism in superconductivity. As a result several effects stemming from the long range nature of diffusion like the Aronov - Altshuler logarithmic corrections to conductivity are less pronounced.