Spin-Polarized Transport in II–VI Magnetic Resonant-Tunneling Devices

Abstract

This paper investigates electronic transport through II-VI semiconductor resonant-tunneling structures containing diluted magnetic impurities. Due to the exchange interaction between the conduction electrons and the impurities, there arises a giant Zeeman splitting in the presence of a moderately low magnetic field. As a consequence, when the quantum well is magnetically doped, the current-voltage characteristics show two peaks corresponding to transport for each spin channel. This behavior is experimentally observed and can be reproduced with a simple tunneling model. The model thus allows to analyze other configurations. First, the magnetic field was further increased, which leads to a spin polarization of the electronic current injected from the leads, thus giving rise to a relative change in the current amplitude. The authors demonstrate that the spin polarization in the emitter can be determined from such a change. Furthermore, in the case of an injector with magnetic impurities, the model shows a large increase in peak amplitude accompanied by a shift of the resonance to higher voltages with increasing fields. It was found that this effect arises from a combination of 3D incident distribution, giant Zeeman splitting, and broad resonance linewidth