Glass Transition in a Two-Dimensional Electron System in Silicon

TL;DR

This study observes large conductivity fluctuations and noise behavior in a low-mobility silicon 2D electron system, indicating a glass transition at a critical electron density and persistent glassy dynamics in the metallic phase.

Contribution

It provides experimental evidence of a glass transition in a 2D electron system in silicon, highlighting the role of electron density and glassy dynamics.

Findings

Conductivity fluctuations increase as electron density decreases.

A sharp change in noise power exponent occurs at a critical density.

Glassy dynamics persist even in the metallic phase.

Abstract

Large fluctuations of conductivity with time are observed in a low-mobility two-dimensional electron system in silicon at low electron densities $n_s$ and temperatures. A dramatic increase of the noise power ($\propto 1/f^{\alpha}$) as $n_s$ is reduced below a certain density $n_g$, and a sharp jump of $\alpha$ at $n_s\approx n_g$, are attributed to the freezing of the electron glass at $n_s = n_g$. The data strongly suggest that glassy dynamics persists in the metallic phase.