Macroscopic transverse drift of long current-induced spin coherence in   two-dimensional electron gases
  We imaged the transport of current-induced spin coherence in a two-dimensional electron gas confined in a triple quantum well. Nonlocal Kerr rotation measurements, based on the optical resonant amplification of the electrically-induced polarization, revealed a large spatial variation of the electron g factor and the efficient generation of a current controlled spin-orbit field in a macroscopic Hall bar device. We observed coherence times in the nanoseconds range transported beyond half-millimeter distances in a direction transverse to the applied electric field. The measured long spin transport length can be explained by two material properties: large mean free path for charge diffusion in clean systems and enhanced spin-orbit coefficients in the triple well. 
F. G. G. Hernandez, S. Ullah, G. J. Ferreira, N. M. Kawahala, G. M.   Gusev, and A. K. Bakarov
cond-mat.mes-hall cond-mat.mtrl-sci