Magnitude of Magnetic Field Dependence of a Possible Selective Spin Filter in ZnSe/Zn_{1-x}Mn_{x}Se Multilayer Heterostructure

摘要

Spin-polarized transport through a band-gap-matched ZnSe/Zn_{1-x}Mn_{x}Se/ZnSe/Zn_{1-x}Mn_{x}Se/ZnSe multilayer structure is investigated. Theresonant transport is shown to occur at different energies for different spinsowing to the split of spin subbands in the paramagnetic layers. It is foundthat the polarization of current density can be reversed in a certain range ofmagnetic field, with the peak of polarization moving towards a strongermagnetic field for increasing the width of central ZnSe layer while shiftingtowards an opposite direction for increasing the width of paramagnetic layer.The reversal is limited in a small-size system. A strong suppression of thespin up component of the current density is present at high magnetic field. Itis expected that such a reversal of the polarization could act as a possiblemechanism for a selective spin filter device.