Magnetization of a two-dimensional electron gas with a second filled subband

TL;DR

This study measures the magnetization of a dual-subband 2D electron gas in GaAs/AlGaAs, revealing unique oscillations explained by a self-consistent model, with additional features at Landau-level crossings.

Contribution

It provides the first detailed measurement and explanation of magnetization oscillations in a dual-subband 2D electron gas, highlighting the role of a field-dependent confining potential.

Findings

Non-1/B-periodic, triangular oscillations observed

Oscillations in magnetization are explained by a self-consistent model

Small oscillations at Landau-level crossings at 1 K

Abstract

We have measured the magnetization of a dual-subband two-dimensional electron gas, confined in a GaAs/AlGaAs heterojunction. In contrast to two-dimensional electron gases with a single subband, we observe non-1/B-periodic, triangularly shaped oscillations of the magnetization with an amplitude significantly less than $1 \mu_{\mathrm{B}}^*$ per electron. All three effects are explained by a field dependent self-consistent model, demonstrating the shape of the magnetization is dominated by oscillations in the confining potential. Additionally, at 1 K, we observe small oscillations at magnetic fields where Landau-levels of the two different subbands cross.