A tunable spin filter in periodic diluted magnetic semiconductor/semiconductor superlattices

We propose a tunable spin filter based on periodic diluted magnetic semiconductor/semiconductor (DMS/S) superlattices. It is found that periodic DMS/S superlattices can filter high efficiently not only spin-up electrons but also spin-down ones over a broad range of incident energies. The positions and widths of spin-filtering bands can be manipulated by adjusting the parameters of the superlattices or the external magnetic field. It is also found that the defect layer within the system generally leads to a strong suppression of spin-dependent transmission and makes the superlattices filter single-energy electrons. The results obtained may lead to potential applications in the field of spintronics. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4733668]