Zero field spin polarization in a 2D paramagnetic resonant tunneling diode

TL;DR

This paper demonstrates that a 2D paramagnetic resonant tunneling diode can achieve over 90% spin polarization of tunneling current at zero magnetic field due to local magnetic order induced by magnetic impurities.

Contribution

It introduces a model showing zero-field spin polarization in a semiconductor resonant tunneling diode caused by magnetic polaron states at quantum well interfaces.

Findings

Resonant tunneling current is highly spin polarized at zero magnetic field.

Local magnetic order lifts degeneracy of tunneling states.

Spin polarization efficiency exceeds 90% without external magnetic field.

Abstract

We study I-V characteristics of an all-II-VI semiconductor resonant tunneling diode with dilute magnetic impurities in the quantum well layer. Bound magnetic polaron states form in the vicinity of potential fluctuations at the well interface while tunneling electrons traverse these interface quantum dots. The resulting microscopic magnetic order lifts the degeneracy of the resonant tunneling states. Although there is no macroscopic magnetization, the resulting resonant tunneling current is highly spin polarized at zero magnetic field due to the zero field splitting. Detailed modeling demonstrates that the local spin polarization efficiency exceeds 90% without an external magnetic field.