Spin gating electrical current

TL;DR

This paper demonstrates a novel spin gating approach using an aluminium single electron transistor with a magnetic gate to measure and control chemical potential anisotropy in GaMnAs, revealing complex magnetic behaviors.

Contribution

It introduces a new method of spin gating that controls charge transport via magnetic properties, not traditional electric gates, in GaMnAs materials.

Findings

Measured uniaxial and cubic chemical potential anisotropy contributions.

Observed non-monotonic isotropic magnetic field dependence of chemical potential.

Explained effects with a $oldsymbol{k}oldsymbol{ullet}oldsymbol{p}$ kinetic exchange model.

Abstract

We use an aluminium single electron transistor with a magnetic gate to directly quantify the chemical potential anisotropy of GaMnAs materials. Uniaxial and cubic contributions to the chemical potential anisotropy are determined from field rotation experiments. In performing magnetic field sweeps we observe additional isotropic magnetic field dependence of the chemical potential which shows a non-monotonic behavior. The observed effects are explained by calculations based on the $\mathbf{k}\cdot\mathbf{p}$ kinetic exchange model of ferromagnetism in GaMnAs. Our device inverts the conventional approach for constructing spin transistors: instead of spin-transport controlled by ordinary gates we spin-gate ordinary charge transport.