Hysteresis in the quantum Hall regimes in electron double quantum well structures

TL;DR

This paper investigates transport hysteresis in electron double quantum well structures, revealing that hysteresis is more pronounced in the even IQHE regime due to larger energy gaps, using a novel measurement technique.

Contribution

It introduces a measurement method fixing magnetic field while sweeping gate voltage to study hysteresis in quantum Hall regimes, highlighting differences between even and odd IQHE states.

Findings

Hysteresis is stronger in the even IQHE regime.

Hysteresis correlates with the energy gap size.

The measurement technique isolates Landau level effects.

Abstract

We present in this paper experimental results on the transport hysteresis in electron double quantum well structures. Exploring the measurement technique of fixing the magnetic field and sweeping a front gate voltage (Vg), we are able to study the hysteresis by varying the top layer Landau level fillings while maintaining a relatively constant filling factor in the bottom layer, allowing us to tackle the question of the sign of Rxx(up)-Rxx(down), where Rxx(up) is the magnetoresistance when Vg is swept up and Rxx(down) when Vg swept down. Furthermore, we observe that hysteresis is generally stronger in the even integer quantum Hall effect (IQHE) regime than in the odd-IQHE regime. This, we argue, is due to a larger energy gap for an even-IQHE state, determined by the Landau level separation, than that for an odd-IQHE state, determined by the Zeeman splitting.