Enhanced quantum oscillatory magnetization and non-equilibrium currents in an interacting two-dimensional electron system in MgZnO/ZnO with repulsive scatterers

TL;DR

This study investigates quantum oscillations and non-equilibrium currents in a MgZnO/ZnO 2D electron system, revealing the impact of residual disorder and electron interactions on magnetic properties at low temperatures.

Contribution

It provides new insights into the microscopic nature of disorder and its influence on quantum oscillations in MgZnO/ZnO heterostructures, highlighting the role of acceptor-like scatterers.

Findings

Observation of sawtooth-like quantum oscillatory magnetization

Detection of spike-like overshoots and non-equilibrium currents

Identification of residual disorder's microscopic nature and density

Abstract

Torque magnetometry at low temperature and in high magnetic fields B is performed on a MgZnO/ZnO heterostructure incorporating a high-mobility two-dimensional electron system. We find a sawtooth-like quantum oscillatory magnetization M(B), i.e., the de Haas-van Alphen (dHvA) effect. At the same time, unexpected spike-like overshoots in M and non-equilibrium currents are observed which allow us to identify the microscopic nature and density of the residual disorder. The acceptor-like scatterers give rise to a magnetic thaw down effect which enhances the dHvA amplitude beyond the electron-electron interaction effects being present in the MgZnO/ZnO heterostructure