Spatial imaging of the spin Hall effect and current-induced polarization in two-dimensional electron gases

• Published in: Nature physics Vol. 1; no. 1; pp. 31 - 35
• Main Authors: Awschalom, D. D, Sih, V, Myers, R. C, Kato, Y. K, Lau, W. H, Gossard, A. C
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.10.2005
• Subjects: Anisotropy; Polarization
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/nphys009

Spin-orbit coupling in semiconductors relates the spin of an electron to its momentum, and provides a pathway for electrically initializing and manipulating electron spins for applications in spintronics and spin-based quantum information processing. This coupling can be regulated with quantum confinement in semiconductor heterostructures through band-structure engineering. Here we investigate the spin Hall effect and current-induced spin polarization in a two-dimensional electron gas confined in (110) AlGaAs quantum wells using Kerr rotation microscopy. In contrast to previous measurements, the spin Hall profile shows complex structure and the current-induced spin polarization is out-of-plane. The experiments map the strong dependence of the current-induced spin polarization to the crystal axis along which the electric field is applied, reflecting the anisotropy of the spin-orbit interaction. These results reveal opportunities for tuning a spin source using quantum confinement and device engineering in non-magnetic materials.