Electrical glassy behavior in granular aluminium thin films

TL;DR

This paper investigates the electrical glassy behavior in granular aluminium thin films, revealing stable conductance fluctuations, persistent anomalous field effects, and true aging phenomena, which deepen understanding of disordered electronic systems.

Contribution

The study demonstrates that glassy electrical behaviors such as conductance fluctuations and aging are present in small granular aluminium films, extending previous macroscopic observations to microscopic scales.

Findings

Reproducible conductance fluctuations in micron-sized samples.

Persistence of anomalous field effect in small samples.

Observation of true aging dependent on cooling time.

Abstract

We present new results obtained by field effect measurements on insulating granular Al thin films. First, reproducible and stable conductance fluctuations are seen in micron size samples as a function of gate voltage. The anomalous field effect and its slow relaxation already known to exist in macroscopic samples are shown to still exist in small samples and to have no influence on the fluctuations pattern. Secondly, "true" aging is demonstrated, i.e. the anomalous field effect relaxation depends on the time elapsed since the cooling, the longer this time the longer it takes for the system to react to a gate voltage change. Interpretations and implications of these findings are discussed.