Electrical generation of pure spin currents in a two-dimensional electron gas

TL;DR

This paper demonstrates a method to generate and measure pure spin currents in a GaAs 2DEG, revealing long spin relaxation lengths and offering a new tool for studying spin dynamics in mesoscopic semiconductor structures.

Contribution

It introduces a nonlocal measurement technique for detecting pure spin currents in GaAs 2DEG with high sensitivity and long relaxation lengths, advancing spintronics research.

Findings

Measured spin relaxation lengths of 30-50 microns.

Achieved high sensitivity in nonlocal measurement geometry.

Demonstrated the technique's potential for studying spin dynamics.

Abstract

Pure spin currents are measured in micron-wide channels of GaAs two-dimensional electron gas (2DEG). Spins are injected and detected using quantum point contacts, which become spin polarized at high magnetic field. High sensitivity to the spin signal is achieved in a nonlocal measurement geometry, which dramatically reduces spurious signals associated with charge currents. Measured spin relaxation lengths range from 30 to 50 microns, much longer than has been reported in GaAs 2DEG's. The technique developed here provides a flexible tool for the study of spin polarization and spin dynamics in mesoscopic structures defined in 2D semiconductor systems.