Dresden 2006 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 9: Poster I

HL 9.73: Poster

Montag, 27. März 2006, 15:15–17:45, P3

Non-invasive detection of charge-rearrangement in a quantum dot — •C. Fricke¹, M. C. Rogge¹, B. Harke², F. Hohls³, M. Reinwald⁴, W. Wegscheider⁴, and R. J. Haug¹ — ¹Institut für Festkörperphysik, Universität Hannover, D-30167 Hannover — ²Max-Planck-Institut für biophysikalische Chemie, Göttingen — ³Cavendish Laboratory, Cambridge, Great Britain — ⁴Angewandte und Experimentelle Physik, Universität Regensburg

We show transport measurements in high magnetic field on a coupled system including a quantum dot and a quantum point contact. We use a GaAs/AlGaAs heterostructure containing a two-dimensional electron system (2DES) 34 nm below the surface. The lateral quantum dot and the quantum point contact (QPC) are defined by the atomic force microscope (AFM) using local anodic oxidation (LAO). We demonstrate electron redistribution on the quantum dot caused by the magnetic field [1]. The dot’s charge configuration is measured by means of a quantum point contact as non-invasive detector. Our device allows to control independently the quantum point contact and all tunnelling barriers of the quantum dot. Thus we are able to measure both the change of the quantum dot charge and also changes of the electron configuration at constant number of electrons on the quantum dot. We use these features to exploit the quantum dot in a high magnetic field where transport through the quantum dot displays the effects of Landau shells and spin blockade. We confirm the internal rearrangement of electrons as function of the magnetic field for a fixed number of electrons on the quantum dot.

[1] C. Fricke et al., Phys. Rev. B 72, 193302 (2005)