Zhen-Gang Zhu1,* and Gang Su2
1Center for Advanced Study, Tsinghua University, Beijing 100084, China 2
College of Physical Sciences, Graduate School of the Chinese Academy of Sciences, P. O. Box 3908, Beijing 100039, China
(Received 17 July 2004; published 23 November 2004)

Abstract:

  Spin-polarized transport through a band-gap-matched ZnSe / Zn₁−xMnxSe / ZnSe / Zn₁−xMnxSe / ZnSe multilayer structure is investigated. The resonant transport is shown to occur at different energies for different spins owing to the split of spin subbands in the paramagnetic layers. It is found that the polarization of current density can be reversed in a certain range of magnetic field, with the peak of polarization moving towards a stronger magnetic field for increasing the width of central ZnSe layer while shifting towards an opposite direction for increasing the width of paramagnetic layer. The reversal is limited in a small-size system. A strong suppression of the spin up component of the current density is present at high magnetic field. It is expected that such a reversal of the polarization could act as a possible mechanism for a selective spin filter device.

DOI: 10.1103/PhysRevB.70.193310     PACS number(s): 75.50.Pp, 72.25.Hg, 72.25.Dc, 73.23.Ad