Origin of Sub-linear Width Dependence of Quantum Hall Breakdown Current

Abstract

We have studied the properties of quantum Hall effect (QHE) breakdown where the critical current increases sub‐linearly with the channel width (sub‐linear type) by using Hall‐bar shaped and Corbino geometry samples made from GaAs/AlGaAs heterostructures. The channel width dependence of critical current in Hall‐bar and the critical voltage in Corbino geometry shows sub‐linear feature. The breakdown current measured in the Hall‐bar with the side gate along the sample boundaries is scarcely affected by the side gate voltage. The experimental results support that the sub‐linear type QHE breakdown is not “edge effect” but the bulk properties of two‐dimensional electron system (2DES). The activation energy of bulk 2DES conductivity in the sub‐linear type sample at QHE plateau is highly current dependent. The possible origin of sub‐linear type QHE breakdown; the localized current distribution in the bulk 2DES and current (electric field) effect on the activation energy in 2DES with small potential fluctuation, is discussed.