从铁磁金属到非磁性半导体的自旋注入

In this paper, a model on electrical spin injection from ferromagnetic metal to non-magnetic semiconductor has been built. This model takes into account not only the diffusion term of the current contribution to the spin polarization in non-magnetic semiconductor (which is a good approximation in the lower current), but also to consider the effect of drift term on spin polarization. We introduce the concepts of the drift length and the effective spin flip length. Drift length decides the contribution of drift term to spin current polarization. In the lower injection, it is much larger than the effective spin flip length in semiconductor, so its influence on spin polarization can be ignored. But the drift length and the effective spin flip length in semiconductor decreases with the current raising, resulting in increasing of diffusion and drift flow\