1/f Noise In Low Density Two-Dimensional Hole Systems In GaAs

TL;DR

This study measures 1/f resistance noise in low-density two-dimensional hole systems in GaAs, revealing behavior that suggests a phase transition or percolation transition below the metal-insulator transition.

Contribution

It provides new experimental data on 1/f noise in low-density 2D hole systems, challenging existing localization models and supporting the phase transition hypothesis.

Findings

Normalized noise power increases as density and temperature decrease.

Temperature dependence of noise is steeper at lower densities.

Results contradict the modulation approach in strong localization regime.

Abstract

Two-dimensional electron or hole systems in semiconductors offer the unique opportunity to investigate the physics of strongly interacting fermions. We have measured the 1/f resistance noise of two-dimensional hole systems in high mobility GaAs quantum wells, at densities below that of the metal-insulator transition (MIT) at zero magnetic field. Two techniques voltage and current fluctuations were used. The normalized noise power SR/R2 increases strongly when the hole density or the temperature are decreased. The temperature dependence is steeper at the lowest densities. This contradicts the predictions of the modulation approach in the strong localization hopping transport regime. The hypothesis of a second order phase transition or percolation transition at a density below that of the MIT is thus reinforced.