Luminescence imaging of photoelectron spin precession during drift in a p-type GaAs microfabricated Hall bar

Using a microfabricated p-type GaAs Hall bar, it is shown that the combined application of co-planar electric and magnetic fields enables the observation of spatial oscillations of the photoluminescence circular polarization due to the precession of drifting spin-polarized photoelectrons. Observation of these oscillations as a function of electric field gives a direct measurement of the minority carrier drift mobility and reveals that the spin coherence length can be tuned up to more than 10μm with electric fields below 1 kV/cm.