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

V. Sih·R. C. Myers·Y. K. Kato·W. H. Lau·A. C. Gossard·D. D. Awschalom
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Abstract

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 exhibits 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.

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V. Sih, R. C. Myers, Y. K. Kato, W. H. Lau, A. C. Gossard, D. D. Awschalom. 2005-06-27. Spatial imaging of the spin Hall effect and current-induced polarization in two-dimensional electron gases. https://doi.org/10.1038/nphys009

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