Spin polarization of electrons with Rashba double-refraction

• Published in: Journal of physics. Condensed matter 2004-12, Vol.16 (50), p.9143-9154
• Main Authors: Marigliano Ramaglia, V, Bercioux, D, Cataudella, V, De Filippis, G, Perroni, C A
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic transport in condensed matter; Electronics; Exact sciences and technology; Magnetic properties and materials; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Nuclear magnetic resonance and relaxation; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Spin polarized transport; Studies of specific magnetic materials; Transistors
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/16/50/005

We demonstrate how the Rashba spin-orbit coupling in semiconductor heterostructures can produce and control a spin-polarized current without ferromagnetic leads. The key idea is to use spin-double refraction of an electronic beam with a nonzero incidence angle. A region where the spin-orbit coupling is present separates the source and the drain without spin-orbit coupling. We show how the transmission and the beam spin polarization critically depend on the incidence angle. The transmission halves when the incidence angle is greater than a limit angle and a significant spin polarization appears. On increasing the spin-orbit coupling one can obtain the modulation of the intensity and of the spin polarization of the output electronic current when the input current is unpolarized. Our analysis shows the possibility of realizing a spin-field-effect transistor based on the propagation of only one mode with the region with spin-orbit coupling, whereas the original Datta and Das device (1990 Appl. Phys. Lett. 56 665) uses the spin precession that originates from the interference between two modes with orthogonal spin.