Metal-insulator transition in two-dimensional electron systems

TL;DR

This paper reviews the phenomenon of a metal-insulator transition in two-dimensional electron systems, highlighting experimental evidence of a metallic phase arising from strong electron interactions contrary to traditional localization theory.

Contribution

It provides a comprehensive overview of experimental findings on the metal-insulator transition in 2D systems, emphasizing the role of strong interactions and magnetic properties.

Findings

Evidence of metallic phase in 2D electron systems

Observation of anomalous magnetic properties near transition

Contradiction of traditional localization theory

Abstract

The interplay between strong Coulomb interactions and randomness has been a long-standing problem in condensed matter physics. According to the scaling theory of localization, in two-dimensional systems of noninteracting or weakly interacting electrons, the ever-present randomness causes the resistance to rise as the temperature is decreased, leading to an insulating ground state. However, new evidence has emerged within the past decade indicating a transition from insulating to metallic phase in two-dimensional systems of strongly interacting electrons. We review earlier experiments that demonstrate the unexpected presence of a metallic phase in two dimensions, and present an overview of recent experiments with emphasis on the anomalous magnetic properties that have been observed in the vicinity of the transition.