Nonuniform current density and spin accumulation in a 1 {\mu}m thick   n-GaAs channel
  The spin accumulation in an n-GaAs channel produced by spin extraction into a (Ga,Mn)As contact is measured by cross-sectional imaging of the spin polarization in GaAs. The spin polarization is observed in a 1 \mum thick n-GaAs channel with the maximum polarization near the contact edge opposite to the maximum current density. The one-dimensional model of electron drift and spin diffusion frequently used cannot explain this observation. It also leads to incorrect spin lifetimes from Hanle curves with a strong bias and distance dependence. Numerical simulations based on a two-dimensional drift-diffusion model, however, reproduce the observed spin distribution quite well and lead to realistic spin lifetimes. 
Bernhard Endres, Mariusz Ciorga, Robert Wagner, Sebastian Ringer,   Martin Utz, Dominique Bougeard, Dieter Weiss, Christian ...
cond-mat.mtrl-sci