1/f noise in a dilute GaAs two-dimensional hole system in the insulating phase

TL;DR

This study investigates 1/f resistance noise in a dilute GaAs two-dimensional hole system at low temperatures, revealing behavior consistent with a percolation model rather than independent particle localization.

Contribution

It provides experimental evidence supporting a percolation-based interpretation of noise and resistance behavior in dilute 2D systems near the insulator transition.

Findings

Resistance shows power-law or activated temperature dependence.

Noise decreases with increasing temperature and density.

Results align with a percolation model over strong localization theories.

Abstract

We have measured the resistance and the 1/f resistance noise of a two-dimensional low density hole system in a high mobility GaAs quantum well at low temperature. At densities lower than the metal-insulator transition one, the temperature dependence of the resistance is either power-like or simply activated. The noise decreases when the temperature or the density increase. These results contradict the standard description of independent particles in the strong localization regime. On the contrary, they agree with the percolation picture suggested by higher density results. The physical nature of the system could be a mixture of a conducting and an insulating phase. We compare our results with those of composite thin films.