Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties

HL 91.27: Poster

Donnerstag, 14. März 2013, 16:00–20:00, Poster A

Two-path Transport Measurements with Bias Dependence on a Triple Quantum Dot — •Monika Kotzian, Maximilian C. Rogge, and Rolf J. Haug — Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany

We present transport measurements on a lateral triple quantum dot with a star-like geometry and one lead attached to each dot. [1] The research on triple quantum dots is motivated by fundamental physics and by the fact that it can work as a single qubit. [2] Our sample design allows to simultaneously measure the conductance along two different paths with two quantum dots in each path. The structure is made with local anodic oxidation by AFM on a GaAs/AlGaAs heterostructure. By controlling the potentials quadruple points with all three dots in resonance can be established. [3,4] Using two of the leads as source and one lead as a drain contact, signatures of three dots can be detected in both transport paths. This setup provides the possibility of applying different bias voltages to the sources of the two paths and detecting excited states of the dots. Transport measurements in one path while varying the source-drain voltage on the other path show interesting features and prove interaction between the transport paths. The measurement results are compared with a simulation of the electrostatics of the triple dot system.

[1] M. C. Rogge, et al., Phys. Rev. B 77, 193306 (2008).

[2] P. Hawrylak, et al., Solid State Comm. 136 (2005), pp. 508-512.

[3] L. Gaudreau, et al., PRL 97, 036807 (2006).

[4] M. C. Rogge, et al., New Journal of Physics 11, 113037 (2009).