Observation of finite excess noise in the voltage-biased quantum Hall regime as a precursor for breakdown

TL;DR

This study measures noise in a quantum Hall system, revealing finite excess noise as a precursor to breakdown, indicating dissipation and prebreakdown phenomena in the quantum Hall regime.

Contribution

It provides the first direct measurement of excess noise in the quantum Hall regime, linking noise characteristics to the breakdown process and dissipation.

Findings

Excess noise is suppressed in the zero-bias QHE state.

Finite excess noise appears in the breakdown regime.

Unexpected excess noise at biases below breakdown suggests prebreakdown dissipation.

Abstract

We performed noise measurements in a two-dimensional electron gas to investigate the nonequilibrium quantum Hall effect (QHE) state. While excess noise is perfectly suppressed around the zero-biased QHE state reflecting the dissipationless electron transport of the QHE state, considerable finite excess noise is observed in the breakdown regime of the QHE. The noise temperature deduced from the excess noise is found to be of the same order as the energy gap between the highest occupied Landau level and the lowest empty one. Moreover, unexpected finite excess noise is observed at a finite source-drain bias voltagesmaller than the onset voltage of the QHE breakdown, which indicates finite dissipation in the QHE state and may be related to the prebreakdown of the QHE.