Effects of conduction band offset on spin-polarized transport through a semimagnetic semiconductor heterostructure

We investigate the role played by the zero-field conduction band offset in spin-dependent transport through a ZnSe/Zn1-xMnxSe heterostructure with a single paramagnetic layer. It is shown that the zero-field band offset can strongly affect features of spin-polarized transport: the spin polarization is greatly weakened for the negative zero-field offset while in the positive case it is drastically enhanced. The reason is that the polarization is determined by the discrepancy between the effective potential for spin-up electrons and that for spin-down ones. Furthermore, the magnitude of the effective potential as well as its configuration are conduction-band-offset dependent and field tunable. (C) 2001 American Institute of Physics.