Critical Behavior of a Strongly Interacting 2D Electron System

TL;DR

The paper presents evidence of a critical transition in a strongly interacting 2D electron system in silicon, marked by a divergence in thermopower at a finite density, indicating a phase change driven by electron interactions.

Contribution

It demonstrates a critical behavior in thermopower indicating a phase transition in a low-disorder 2D electron system, with a critical density independent of disorder.

Findings

Thermopower diverges at a finite density $n_t$

Critical form $(-T/S) o (n_s - n_t)^x$ with $x oughly 1$

Evidence for an interaction-driven phase transition

Abstract

With decreasing density $n_s$ the thermopower $S$ of a low-disorder 2D electron system in silicon is found to exhibit a sharp increase by more than an order of magnitude, tending to a divergence at a finite, disorder-independent density $n_t$ consistent with the critical form $(-T/S) \propto (n_s-n_t)^x$ with $x=1.0\pm 0.1$ ($T$ is the temperature). Our results provide clear evidence for an interaction-induced transition to a new phase at low density in a strongly-interacting 2D electron system.