Phase diagram of the metal-insulator transition in 2D electronic systems

TL;DR

This paper presents a detailed phase diagram for the metal-insulator transition in 2D electronic systems, highlighting how disorder and carrier density influence the nature and critical points of the transition.

Contribution

It introduces a self-consistent method incorporating disorder and Coulomb correlations to quantitatively map the metal-insulator phase diagram in 2D systems.

Findings

Two types of transitions: continuous at rs<8 and discontinuous at higher rs

Critical disorder level decreases with lower carrier density

System remains insulating at very low carrier densities

Abstract

We investigated the interdependence of the effects of disorder and carrier correlations on the metal-insulator transition in two-dimensional electronic systems. We present a quantitative metal-insulator phase diagram. Depending on the carrier density we find two different types of metal-insulator transition - a continuous localization for rs=<8 and a discontinuous transition at higher rs. The critical level of disorder at the transition decreases with decreasing carrier density. At very low carrier densities we find that the system is always insulating. The value of the conductivity at the transition is consistent with recent experimental measurements. The self-consistent method which we have developed includes the effects of both disorder and correlations on the transition, using a density relaxation theory with the Coulomb correlations determined from numerical simulation data.