Theory of Spin Hall conductivity in n-doped GaAs
  We develop a theory of extrinsic spin currents in semiconductors, resulting from spin-orbit coupling at charged scatterers, which leads to skew scattering and side jump contributions to the spin Hall conductance. Applying the theory to bulk n-GaAs, without any free parameters, we find spin currents that are in reasonable agreement with recent experiments by Kato et al. [Science 306, 1910 (2004)]. 
Hans-Andreas Engel, Bertrand I. Halperin, and Emmanuel I. Rashba