SPONTANEOUS SPIN POLARIZATION OF ELECTRONS IN SiGe/Si HETEROSTRUCTURES
Abstract
The spin-dependent electron transmission phenomenon in an SiGe/Si/SiGe resonant semiconductor heterostructure is employed theoretically to investigate the output transmission current polarization at zero magnetic field. Transparency of electron transmission is calculated as a function of electron energy as well as the well width, within the one electron band approximation along with the spin-orbit interaction. Enhanced spin-polarized resonant tunneling in the heterostructure due to Dresselhaus and Rashba spin-orbit coupling induced splitting of the resonant level is observed. We predict that a spin-polarized current spontaneously emerges in this heterostructure and we estimate theoretically that the polarization can reach 100%. This effect could be employed in the fabrication of spin filters, spin injectors, and detectors based on nonmagnetic semiconductors.
