  A quantitative estimation of spin drift velocity in highly doped n-type
silicon (Si) at 8 K is presented in this letter. A local two-terminal Hanle
measurement enables the detection of a modulation of spin signals from the Si
as a function of an external electric field, and this modulation is analyzed by
using a spin drift-diffusion equation and an analytical solution of the
Hanle-type spin precession. The analyses reveal that the spin drift velocity is
linearly proportional to the electric field. The contribution of the spin drift
effect to the spin signals is crosschecked by introducing a modified nonlocal
four-terminal method.
