Spin Diffusion and the Role of Screening Effects in Semiconductors

Abstract—The electron spin properties in semi-conductors are of great interest because of their potential in future spin-driven microelectronic de-vices. We performed simulations on electron spin injection in an n-doped silicon bar from a magnetic semiconductor with spin-dependent conductivity. A variation of doping can introduce charge accumu-lation/depletion layer at the interface. We found substantial spin transport differences, when spins are introduced through a charge accumulated and a charge depleted interface layer. Special attention is paid to a possible spin injection efficiency enhance-ment compared to the existing theory at the charge neutrality condition. We found that at a fixed bulk spin polarization, the efficiency increases, if spins are injected from a charge depleted source. Index Terms—Spin transport, spin injection, space-charge region. I