Imaging spin flows in semiconductors subject to electric, magnetic, and strain fields

TL;DR

This study uses scanning Kerr microscopy to visualize and control spin-polarized electron flows in GaAs semiconductors under electric, magnetic, and strain fields, revealing strain-induced spin-orbit coupling effects.

Contribution

It provides the first direct imaging of spin flows in semiconductors influenced by strain, demonstrating strain's role in spin-orbit coupling.

Findings

Direct imaging of spin-polarized electron flow in GaAs

Strain induces spin precession via spin-orbit coupling

Controlled strain affects spin dynamics significantly

Abstract

Using scanning Kerr microscopy, we directly acquire two-dimensional images of spin-polarized electrons flowing laterally in bulk epilayers of n:GaAs. Optical injection provides a local dc source of polarized electrons, whose subsequent drift and/or diffusion is controlled with electric, magnetic, and - in particular - strain fields. Spin precession induced by controlled uniaxial stress along the <110> axes demonstrates the direct k-linear spin-orbit coupling of electron spin to the shear (off-diagonal) components of the strain tensor.