Spin-polarized current oscillations in diluted magnetic semiconductor multiple quantum wells

TL;DR

This paper investigates how spin-polarized current oscillations arise in diluted magnetic semiconductor multiple quantum wells due to nonlinear charge transport and exchange interactions, revealing controllable spin dynamics.

Contribution

It introduces a detailed numerical analysis of spin-dependent oscillations in magnetic quantum wells, highlighting the influence of magnetic well distribution on spin polarization behavior.

Findings

Spin-polarized tunneling currents can develop self-sustained oscillations.

The amplitude of spin oscillations depends on magnetic well placement.

Spin polarization can be manipulated experimentally.

Abstract

We study the spin and charge dynamics of electrons in n-doped II--VI semiconductor multiple quantum wells when one or more quantum wells are doped with Mn. The interplay between strongly nonlinear inter-well charge transport and the large tunable spin-splitting induced by exchange interactions with spin-polarized Mn ions produces interesting new spin dependent features. The tunneling current between quantum wells can be strongly spin polarized and, under certain conditions, can develop self sustained oscillations under a finite dc voltage. The spin polarization oscillates in both magnetic and nonmagnetic quantum wells and the time average in magnetic wells can differ from its zero-voltage value. Our numerical simulations demonstrate that the amplitude of the spin polarization oscillations depends on the distribution of magnetic wells within the sample. We discuss how the spin polarized current and the spin polarization of the quantum wells can be tailored experimentally.