Metal-insulator transition and glassy behavior in two-dimensional electron systems

TL;DR

This paper investigates the metal-insulator transition in two-dimensional silicon electron systems, revealing glassy freezing, long-range correlations, and the influence of disorder on the metallic glass phase.

Contribution

It provides experimental evidence of glassy behavior and long-range correlations near the MIT in 2D electron systems, highlighting the role of disorder.

Findings

Glassy freezing occurs near the MIT in 2D silicon systems.

The metallic glass phase width depends strongly on disorder.

Long-range correlations are present in the glassy phase.

Abstract

Studies of low-frequency resistance noise demonstrate that glassy freezing occurs in a two-dimensional electron system in silicon in the vicinity of the metal-insulator transition (MIT). The width of the metallic glass phase, which separates the 2D metal and the (glassy) insulator, depends strongly on disorder, becoming extremely small in high-mobility (low-disorder) samples. The glass transition is manifested by a sudden and dramatic slowing down of the electron dynamics, and by a very abrupt change to the sort of statistics characteristic of complicated multistate systems. In particular, the behavior of the second spectrum, an important fourth-order noise statistic, indicates the presence of long-range correlations between fluctuators in the glassy phase, consistent with the hierarchical picture of glassy dynamics.