Electrical detection of spin accumulation in a p-type GaAs quantum well

TL;DR

This paper demonstrates electrical detection of spin accumulation in a p-type GaAs quantum well via tunneling from ferromagnetic electrodes, revealing insights into spin polarization and relaxation in semiconductor structures.

Contribution

It introduces a method to electrically detect spin accumulation in a GaAs quantum well using ferromagnetic tunneling, highlighting the role of spin relaxation times.

Findings

Spin-polarized current injection from GaMnAs into GaAs quantum well.

Detection of spin accumulation through tunneling magnetoresistance.

Large spin effects depend on hole spin relaxation times.

Abstract

We report on experiments in which a spin-polarized current is injected from a $GaMnAs$ ferromagnetic electrode into a $GaAs$ quantum well through an AlAs barrier. The resulting spin polarization in the GaAs well is detected by measuring how the current, tunneling to a second $GaMnAs$ ferromagnetic electrode, depends on the orientation of its magnetization. Our results can be accounted for the non-relaxed spin splitting of the chemical potential, that is spin accumulation, in the $GaAs$ well. We discuss the conditions on the hole spin relaxation time in GaAs that are required to obtain the large effects we observe.