Critical Behavior of a Strongly Disordered 2D Electron System: The Cases of Long-Range and Screened Coulomb Interactions

TL;DR

This paper investigates the metal-insulator transition in a highly disordered 2D electron system, showing that the transition's critical behavior is unaffected by whether Coulomb interactions are long-range or screened.

Contribution

It demonstrates that the critical behavior of the 2D metal-insulator transition is independent of Coulomb interaction range in highly disordered systems.

Findings

Critical exponents are consistent across screened and unscreened Coulomb interactions.

The metal-insulator transition is disorder-driven and not significantly influenced by interaction range.

Scaling behavior supports a disorder-dominated 2D MIT.

Abstract

A study of the temperature (T) and density (n_s) dependence of conductivity \sigma(n_s,T) of a highly disordered, two-dimensional (2D) electron system in Si demonstrates scaling behavior consistent with the existence of a metal-insulator transition (MIT). The same critical exponents are found when the Coulomb interaction is screened by the metallic gate and when it is unscreened or long range. The results strongly suggest the existence of a disorder-dominated 2D MIT, which is not directly affected by the range of the Coulomb interactions.