Nathaniel P. Stern, David W. Steuerman, Shawn Mack, Art C. Gossard, and David D. Awschalom.  “Time-resolved dynamics of the spin Hall effect.” Nature Physics 4, 843 (2008).
Related News and Views article: M. Duckheim and D. Loss. Nature Phys. 4, 836 (2008).             
doi:10.1038/nphys1076