Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 70: Spintronics: Mobile electrons and holes (with MA/TT)

HL 70.9: Talk

Thursday, March 19, 2015, 12:15–12:30, ER 164

Boundary dependent spin manipulation via Rashba-SOC — •Phillipp Reck and Klaus Richter — Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany

Besides spin injection, controlled spin manipulation is a major aspect of active spintronic devices such as spin transistors. In a two dimensional electron gas (2DEG), this manipulation is often achieved by Rashba spin orbit coupling (SOC).

We study numerically the effects of a non-trivial deformation of a wire (quasi 1DEG) on the spin evolution of an initially spin polarized wave packet exposed to Rashba SOC. To make sure that the wave packet follows the deformation, we apply additionally a magnetic field to get edge states, which are resistant to impurity scattering. The benefit of the deformation is the higher variability of the spin state: Without the deformation, the spin precesses on the Bloch sphere around one fixed axis, whereas the deformation changes continuously the orientation of the precession axis leading to a more complex spin evolution. Thus, it is possible, e. g., to create either a x-, y- or z-spin polarization by only changing the Rashba SOC, but not the geometry.

A generalization is a wire with a periodic deformation. Because of the constant out-of-plane magnetic field and an in-plane rotating effective magnetic field due to SOC, one could engineer spin resonance effects.