  Electrically generated spin accumulation due to the spin Hall effect is
imaged in n-GaAs channels using Kerr rotation microscopy, focusing on its
spatial distribution and time-averaged behavior in a magnetic field.
Spatially-resolved imaging reveals that spin accumulation observed in
transverse arms develops due to longitudinal drift of spin polarization
produced at the sample boundaries. One- and two-dimensional drift-diffusion
modeling is used to explain these features, providing a more complete
understanding of observations of spin accumulation and the spin Hall effect.
