Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster 1
HL 13.58: Poster
Montag, 26. März 2007, 15:00–17:30, Poster A
Spectroscopy of quantum dots with ballistic electrons — •Ines Hense1, Christian Praetorius1, Ralf Scheibner1, Markus König1, Carsten Danz1, Dirk Reuter2, Andreas Wieck2, Hartmut Buhmann1, and Laurens Molenkamp1 — 1Physikalisches Institut, Lehrstuhl für Experimentelle Physik 3, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. — 2Lehrstuhl für angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany.
In contrast to conventional methods ballistic electron injection via quantum point contacts (QPC) assures that the quantum dot (QD) system remains in undisturbed thermal equilibrium with its leads throughout the measurement. This is important especially if hybridisation effects between QD states and the leads are expected.
Here, we present data on gate defined GaAs QDs with opposed QPC injectors in a distance of 2 µm, which is well below the elastic mean free path. Using an ac+dc electron injection and lock-in detection the energy selective QD transmission spectra can be explored in a wide parameter range. The non-local resistance and the transmission clearly reflect the energy spectrum of the QD under investigation. Special attention is paid to the regime where spin correlations (e.g. Kondo effect) dominate the transport properties of the QD system.