Nonequilibrium Magnetization of a Two-Dimensional Electron Gas in a Static Magnetic Field

TL;DR

This study measures the orbital magnetization in a 2D electron gas under static magnetic fields, revealing strong nonequilibrium signals likely caused by changes in electronic state areas rather than eddy currents.

Contribution

It identifies a new potential source of nonequilibrium magnetization related to the changing areas of electronic states during Fermi energy sweeps, challenging previous assumptions.

Findings

Strong nonequilibrium magnetization signals observed at low temperatures.

Signals likely originate from changes in the area of electronic states, not eddy currents.

Data obtained using a sensitive DC torque magnetometer on GaAs-AlGaAs heterostructures.

Abstract

Using a sensitive DC torque magnetometer we measure the orbital magnetization by sweeping the density at fixed magnetic fields on GaAs-AlGaAs heterostructures. At low temperatures strong nonequilibrium magnetization signals dominate the data. In literature the observation of nonequilibrium signals are often associated with eddy currents generated by sweeping the magnetic field. The elimination of a changing magnetic field then poses a question regarding the origin of these signals. Our data suggests another source of nonequilibrium magnetization potentially due to the change of area occupied by compressible and incompressible states as one sweeps the Fermi energy from one Landau level to the next.