Control of Spin Relaxation Anisotropy by Spin-Orbit-Coupled Diffusive Spin Motion

Abstract

Spatiotemporal spin dynamics under spin-orbit interaction is investigated in a (001) GaAs twodimensional electron gas using magneto-optical Kerr rotation microscopy. Spin polarized electrons are diffused away from the excited position, resulting in spin precession because of the diffusioninduced spin-orbit field. Near the cancellation between spin-orbit field and external magnetic field, the induced spin precession frequency depends nonlinearly on the diffusion velocity, which is unexpected from the conventional linear relation between the spin-orbit field and the electron velocity. This behavior originates from an enhancement of the spin relaxation anisotropy by the electron velocity perpendicular to the diffused direction. We demonstrate that the spin relaxation anisotropy, which has been regarded as a material constant, can be controlled via diffusive electron motion.

Electrical control of spin relaxation anisotropy during drift transport in a two-dimensional electron gas

“…Very recently, it was shown that the spin relaxation anisotropy can be controlled by diffusive motion [21], in complement to the extensive literature for stationary spins in GaAs * felixggh@if.usp.br systems [22][23][24][25] including high mobility samples [26,27]. Here, we demonstrate electrical control during drift transport in a 2DEG confined in a wide QW occuping two-subbands.…”