Conductance fluctuations at the quantum Hall plateau transition

TL;DR

This paper investigates conductance fluctuations in the quantum Hall regime, revealing universal behavior with reduced amplitude and contrasting temperature dependencies of dephasing and scaling lengths.

Contribution

It provides new insights into the temperature dependence and amplitude of conductance fluctuations in the quantum Hall regime, highlighting differences in characteristic length scales.

Findings

Conductance fluctuations match universal conductance fluctuation expectations but with reduced amplitude.

Dephasing length scales as T^{-1/2}, differing from the T^{-1} scaling of the quantum Hall transition width.

Temperature dependence of fluctuations aligns with metallic behavior in the quantum Hall regime.

Abstract

We analyze the conductance fluctuations observed in the quantum Hall regime for a bulk two-dimensional electron system in a Corbino geometry. We find that characteristics like the power spectral density and the temperature dependence agree well with simple expectations for universal conductance fluctuations in metals, while the observed amplitude is reduced. In addition, the dephasing length $L_\Phi \propto T^{-1/2}$, which governs the temperature dependence of the fluctuations, is surprisingly different from the scaling length $L_{sc}\propto T^{-1}$ governing the width of the quantum Hall plateau transition.