Dependences of spin polarization on the control parameters in the spin-polarized injection through the magnetic p-n junction

Effective spin-polarized injection from magnetic semiconductor (MS)to nonmagnetic semiconductor (NMS) has been highlighted in recentyears. In this paper we study theoretically the dependence ofnonequilibrium spin polarization (NESP) in NMS during spin-polarizedinjection through the magnetic p-n junction. Based on the theory insemiconductor physics, a model is established and the boundaryconditions are determined in the case of no external spin-polarizedinjection and low bias. The control parameters that may influence theNESP in NMS are indicated by calculating the distribution of spinpolarization. They are the doping concentrations, the equilibriumspin polarization in MS and the bias. The effective spin-polarizedinjection can be realized more easily by optimizing the aboveparameters.