Regensburg 2007 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 11: Quantum dots and wires: Transport properties I
HL 11.5: Talk
Monday, March 26, 2007, 15:45–16:00, H15
Transportmeasurements on quantum dots formed in a GaAs/AlGaAs quantum ring — •A. Mühle1, R. J. Haug1, and W. Wegscheider2 — 1Institut für Festkörperphysik, Universität Hannover, D-30167 Hannover — 2Angewandte und Experimentelle Physik, Universität Regensburg, D-92040 Regensburg
We present transport measurements of a quantum ring formed in a GaAs/AlGaAs heterostructure. This ring was fabricated by atomic force microscope lithography utilizing 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.
When the structure is operated in the regime with weak coupling to the leads, sweeping the gates shows different sets of Coulomb-blockade lines, thus revealing the existence of three different dots formed in the arms of the ring.
By analyzing the structure’s transport features, the dots are characterized and their spatial distribution in the ring is determined.
[1] U. F. Keyser et al., Phys. Rev. Lett. 90, 196601-1 (2003)