Topological oscillations of the magnetoconductance in disordered GaAs layers

TL;DR

This paper reports on topological oscillations in magnetoconductance observed in disordered GaAs layers, which are explained by topological scaling effects related to the quantum Hall effect, distinct from Landau quantization oscillations.

Contribution

It demonstrates the existence of topological oscillations in magnetoconductance in disordered GaAs layers and explains them using the unified scaling theory of quantum Hall effects.

Findings

Oscillations occur without Landau level density of states oscillations.

Experimental observations match the predictions of the topological scaling theory.

Oscillations are observed in the extreme quantum limit of magnetic field.

Abstract

Oscillatory variations of the diagonal ($G_{xx}$) and Hall ($G_{xy}$) magnetoconductances are discussed in view of topological scaling effects giving rise to the quantum Hall effect. They occur in a field range without oscillations of the density of states due to Landau quantization, and are, therefore, totally different from the Shubnikov-de Haas oscillations. Such oscillations are experimentally observed in disordered GaAs layers in the extreme quantum limit of applied magnetic field with a good description by the unified scaling theory of the integer and fractional quantum Hall effect.