Figure 1
Illustration: Alan Stonebraker

Figure 1: Electrically-injected electrons become spin polarized through two different mechanisms during nominally “simple” transport in semiconductors. Electrons can experience anisotropic spin scattering from impurities in the presence of spin-orbit coupling, producing the spin Hall effect where “up” and “down” spins (green arrows) accumulate at opposite edges of the channel. In addition, symmetry-related spin-orbit fields can produce a homogeneous electron spin polarization throughout the channel (blue arrows).