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

TL;DR

This study investigates how magnetic field strength influences spin-polarized transport in a multilayer heterostructure, revealing potential for magnetic-field-controlled spin filtering in nanoscale devices.

Contribution

It demonstrates the magnetic field dependence of spin polarization reversal in ZnSe/ZnMnSe multilayers, proposing a mechanism for a selective spin filter based on this effect.

Findings

Spin polarization can be reversed by magnetic field within certain ranges.

The polarization peak shifts with layer width modifications.

High magnetic fields suppress spin-up current components.

Abstract

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. 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.