Electron glass signatures up to room temperature in disordered insulators

TL;DR

This study demonstrates that electron glass signatures, including memory dips and slow relaxation, are observable at room temperature in various disordered insulators, extending previous low-temperature findings.

Contribution

The paper provides the first evidence of electron glass effects at room temperature in four different disordered insulating systems.

Findings

Memory dips observed in all four systems at room temperature

Memory dips relax slowly over days, indicating non-equilibrium states

Electrical glassy effects extend from cryogenic to room temperatures

Abstract

This paper describes the observation of non-equilibrium field effects at room temperature in four disordered insulating systems: granular Al, discontinuous Au, amorphous NbSi and amorphous InOx thin films. The use of wide enough gate voltage ranges and a cautious analysis of the data allow us to uncover memory dips, the advocated hallmark of the electron glass, in the four systems. These memory dips are found to relax slowly over days of measurements under gate voltage changes, reflecting the impossibility for the systems to reach an equilibrium state within experimentally accessible times. Our findings demonstrate that these electrical glassy effects, so far essentially reported at cryogenic temperatures, actually extend up to room temperature.