Polarization of electron spin in two barrier system based on semimagnetic semiconductors

Abstract

The spin-dependent tunneling of electrons through a two barrier semiconductor heterostructure with a semimagnetic layer was investigated. It was shown that the resonant level splitting in the semimagnetic well under an external magnetic field allows achieving a high level of spin polarization of the current flowing through the proposed spin filter. The dependence of the polarization depth on the parameters of the sample was calculated in the two component diffusion transport model.

Semiconductor spintronics

“…By employing an additional semimagnetic emitter contact it has been shown theoretically (Egues et al, 2001) that the voltage-dependent magnetoresistance should exhibit robust features like spin split kinks and beating patterns in the case of single barrier and double barrier structures, respectively. The theoretical investigation of asymmetric tunnel structures with differently doped paramagnetic layers reveal high spin filtering effects of up to nearly 100% for suitable magnetic and electric fields in the case of conduction electrons in ZnSe-based structures (Zhai et al, 2003;Zhu and Su, 2004;Papp et al, 2005Papp et al, , 2006Saffarzadeh et al, 2005) as well as for holes and electrons in CdTe/Cd 1−x Mn x Te heterosystems (Malkova and Ekenberg, 2002;Gnanasekar and Navaneethakrishnan, 2006;Lev et al, 2006). Recently, Borza et al (2007) investigated the interesting possibility of an electric field manipulation of the electronic states in a two-partitioned quantum well, which consists of a magnetic and nonmagnetic layer, resulting in the forming of a potential step in the quantum well for one spin component, while the other experiences a deeper well in the magnetic layer region.…”