Dresden 2009 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 17: Quantum wires: Optical and transport properties
HL 17.9: Vortrag
Dienstag, 24. März 2009, 12:30–12:45, BEY 154
Non-local Aharonov-Bohm conductance oscillations in an asymmetric ballistic quantum ring — •S. S. Buchholz1, S. F. Fischer1, U. Kunze1, D. Reuter2, and A. D. Wieck2 — 1Werkstoffe und Nanoelektronik, Ruhr-Universität Bochum — 2Angewandte Festkörperphysik, Ruhr-Universität Bochum
We investigate ballistic transport and quantum interference in a nanoscale quantum wire loop fabricated as a GaAs/AlGaAs field-effect heterostructure [1]. Our device consists of two equally wide electron waveguides, a bent and a straight one, which orthogonally intersect twice forming an asymmetric ring like structure. Four-terminal measurements of current and voltage characteristics as a function of top gate voltages show negative remote bend resistance as a clear signature of ballistic transport. In perpendicular magnetic fields phase-coherent transport leads to Aharonov-Bohm (AB) conductance oscillations which show equal amplitudes in the local and the non-local measurement at a temperature of 1.5 K and above. We attribute this novel observation to the symmetry of the orthogonal cross junctions connecting the four quantum wire leads with the asymmetric quantum wire ring. [1] S.S. Buchholz, S.F. Fischer, U. Kunze, D. Reuter, A.D. Wieck, arXiv:0811.3150 (2008).