Spin-dependent resonant tunneling in ZnSe/ZnMnSe heterostructures

TL;DR

This study investigates how resonant states influence spin transport in ZnSe/ZnMnSe heterostructures, revealing that layer composition and geometry significantly affect spin polarization and current behavior under electric and magnetic fields.

Contribution

It introduces a detailed analysis of spin-dependent resonant tunneling in heterostructures with variable layer thickness and composition using the transfer matrix method.

Findings

ZnMnSe layers act as effective spin filters.

Resonant levels shift with ZnSe layer thickness, causing oscillations in spin current.

Spin polarization depends strongly on layer thickness and bias.

Abstract

Using the transfer matrix method and the effective-mass approximation, the effect of resonant states on spin transport is studied in ZnSe/ZnMnSe/ZnSe/ZnMnSe/ZnSe structures under the influence of both electric and magnetic fields. The numerical results show that the ZnMnSe layers, which act as spin filters, polarize the electric currents. Variation of thickness of the central ZnSe layer shifts the resonant levels and exhibits an oscillatory behavior in spin current densities. It is also shown that the spin polarization of the tunneling current in geometrical asymmetry of the heterostructure where two ZnMnSe layers have different Mn concentrations, depends strongly on the thickness and the applied bias.