Low-Temperature Collapse of Electron Localisation in Two Dimensions

TL;DR

This study provides experimental evidence that a strongly interacting two-dimensional electron system transitions from insulating to metallic behavior at low temperatures, even with high resistivity, challenging traditional localization theories.

Contribution

It demonstrates a temperature-induced insulator-to-metal transition in a disordered 2DES with strong interactions, observed on mesoscopic scales.

Findings

Transition from insulating to metallic behavior at low temperatures.

Persistence of metallic behavior despite resistivity exceeding h/e^2.

Evidence of instability of the insulating phase in strongly interacting 2DES.

Abstract

We report direct experimental evidence that the insulating phase of a disordered, yet strongly interacting two-dimensional electron system (2DES) becomes unstable at low temperatures. As the temperature decreases, a transition from insulating to metal-like transport behaviour is observed, which persists even when the resistivity of the system greatly exceeds the quantum of resistivity h/e^2. The results have been achieved by measuring transport on a mesoscopic length-scale while systematically varying the strength of disorder.