  A systematic investigation of spin transport properties in silicon at 8 K by
using a non-local geometry is presented. The spin injection signal in the
non-local scheme is found to increase in proportion to the evolution of bias
electric currents. Theoretical fittings using the Hanle-type spin precession
signals reveal that the spin polarization of the transported spin in the Si is
much less affected by the change in the bias electric current compared with a
case of the other spin devices, which induces a unique bias dependence of the
spin signals.
