Investigation of spin drift velocity and the modulation of spin signals under spin drift in highly-doped n-type Si

Spin drift enables to modulate a spin transport length scale in semiconductor.\footnote{Z.G. Yu and M.E. Flatte, Phys. Rev. B 66, 201202(R) (2002).} We have experimentally investigated a role of spin drift in spin transport in highly-doped n-Si, i.e., the modulation of a spin transport length scale by using an electrical spin transport method.\footnote{M. Kameno et al., Appl. Phys. Lett. 101, 122413 (2012).} The results directly show that spin drift becomes prominent in spin transport in semiconductor. In addition, spin drift velocity in the highly-doped Si channel was quantitatively estimated by introducing a new experimental technique.\footnote{M. Kameno et al., Appl. Phys. Lett. 104, 092409 (2014).} It was revealed that Hanle-type spin precession signals from the Si were modulated by spin drift and were theoretically reproduced.