Robustness of the quantum Hall effect, sample size versus sample topology, and quality control management of III-V molecular beam epitaxy

TL;DR

This study demonstrates the robustness of the integer quantum Hall effect in large, macroscopic III-V heterostructure samples, confirming its stability across different geometries and inhomogeneities, which supports wider application potential.

Contribution

It provides experimental evidence that the IQHE remains robust in large-area samples and compares different geometries and inhomogeneity effects, advancing understanding of sample size and topology impacts.

Findings

IQHE remains robust in large samples with areas 10,000 times larger than standard.

Wide quantum Hall plateaux develop at small filling factors in large samples.

Sample inhomogeneities do not significantly disrupt the IQHE robustness.

Abstract

We measure the IQHE on macroscopic (1.5cm x 1.5cm) "quick 'n' dirty" prepared III-V heterostructure samples with van der Pauw and modified Corbino geometries at 1.3 K. We compare our results with (i) data taken on smaller specimens, among them samples with a standard Hall bar geometry, (ii) results of our numerical analysis taking inhomogenities of the 2DEG into account. Our main finding is a confirmation of the expected robustness of the IQHE which favours the development of wide plateaux for small filling factors and very large sample sizes (here with areas 10,000 times larger than in standard arrangements).