Resistance Noise Scaling in a Dilute Two-Dimensional Hole System in GaAs

TL;DR

This study measures resistance noise in a high mobility GaAs 2D hole system near the metal-insulator transition, revealing critical behavior consistent with a percolation transition and providing insights into the transition's nature.

Contribution

It presents the first detailed resistance noise analysis near the 2D metal-insulator transition in GaAs, showing scaling behavior indicative of a percolation transition.

Findings

Resistance noise increases as hole density decreases.

Noise scales with resistance as $S_R/R^2 \\sim R^{2.4}$.

Conductivity behavior suggests a critical transition at a density below the MIT point.

Abstract

We have measured the resistance noise of a two-dimensional (2D)hole system in a high mobility GaAs quantum well, around the 2D metal-insulator transition (MIT) at zero magnetic field. The normalized noise power $S_R/R^2$ increases strongly when the hole density p_s is decreased, increases slightly with temperature (T) at the largest densities, and decreases strongly with T at low p_s. The noise scales with the resistance, $S_R/R^2 \sim R^{2.4}$, as for a second order phase transition such as a percolation transition. The p_s dependence of the conductivity is consistent with a critical behavior for such a transition, near a density p* which is lower than the observed MIT critical density p_c.