Dresden 2003 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 49: Poster II

HL 49.14: Poster

Donnerstag, 27. März 2003, 16:30–19:00, HSZ/P2

Rashba spin-orbit interaction in mesoscopic rings — •Frank E. Meijer, Alberto F. Morpurgo, and Teun M. Klapwijk — Delft University of Technology, Lorentzweg 1, 2628CJ Delft, The Netherlands

The possibility to create spin polarization in semiconductor heterostructures and controlling the spin-direction will lead to new spin-based devices, in contrast to traditional charge-based devices. We focus on a mechanism that can control the spin-direction electrically, called Rashba spin-orbit (SO) interaction. We have studied theoretically the effect of strong SO interaction in a multi-mode ring. Its behaviour is completely different from a single-mode ring or 2D plane due to band-mixing between bands with opposite spins. This results in spin persistent currents in the ring, but not in spin-polarization or spin-accumulation. By applying a magnetic field perpendicular to the ring, the clockwise and anti-clockwise currents are spatially separated. We show numerically that the resulting lowest edge states have essentially parallel spin. This results in partly spin-polarized edge currents and a finite local spin-accumulation. These results are not limited to a quasi-1D ring structure, but also hold for a quasi-1D wire.