Luminescence imaging of photoelectron spin precession during drift in p-type GaAs

TL;DR

This study demonstrates that applying electric and magnetic fields to p-type GaAs allows direct imaging of spin precession during electron drift, revealing long spin coherence lengths and enabling mobility measurements via luminescence polarization oscillations.

Contribution

It introduces a novel luminescence imaging technique to observe spin precession in drifting electrons in p-GaAs at 50 K, providing new insights into spin coherence and mobility.

Findings

Spin precession oscillations observed at 50 K

Spin coherence preserved over 25 μm at 800 V/cm

Mobility measured through polarization oscillations

Abstract

Using a microfabricated, p-type GaAs Hall bar, is it shown that the combined application of co-planar electric and magnetic fields enables the observation at 50 K of spatial oscillations of the photoluminescence circular polarization due to the precession of drifting spin-polarized photoelec- trons. Observation of these oscillations as a function of electric field E gives a direct measurement of the minority carrier drift mobility and reveals that, for E = 800 V/cm, spin coherence is preserved over a length as large as 25{\mu}m.