Berlin 2005 – scientific programme
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HL: Halbleiterphysik
HL 58: Poster IIb
HL 58.2: Poster
Tuesday, March 8, 2005, 16:30–19:00, Poster TU F
Magnetotransport measurements on GaAs/AlGaAs quantum rings — •A. Mühle1, R. J. Haug1, W. Wegscheider2, and M. Bichler3 — 1Institut für Festkörperphysik, Universität Hannover, D-30167 Hannover — 2Angewandte und Experimentelle Physik, Universität Regensburg, D-92040 Regensburg — 3Walter Schottky Institut, TU München, D-85748 Garching
We present transport measurements done in dependence of an external magnetic field on quantum rings of different sizes on the surface of GaAs/AlGaAs heterostructures. These rings were fabricated by atomic force microscope lithography utilising local anodic oxidation [1]. Using in-plane gates, the energy of the electrons in the arms of the rings as well as the coupling of the structures to the leads can be controlled.
While sweeping the magnetic field in the regime with only one occupied subband and a conductivity of a few e2/h, Aharonov-Bohm oscillations appear that show a modulation of their amplitude with a period of several hundred mT.
We attribute this phenomenon to spin-orbit effects.
[1] U. F. Keyser et al., Phys. Rev. Lett. 90, 196601-1 (2003)