Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 6: Quantum dots and wires: Transport properties I
HL 6.8: Vortrag
Montag, 27. März 2006, 12:00–12:15, BEY 118
Freely Suspended Quantum Dots — •Clemens Rössler1, Stefan Ludwig1, Jörg P. Kotthaus1, Dieter Schuh2, and Werner Wegscheider2 — 1Center for NanoScience and Sektion Physik, Ludwig-Maximilians-Universität, Geschwister Scholl Platz 1, 80539 München, Germany — 2Institut für Angewandte und Experimentelle Physik, Universität Regensburg, 93040 Regensburg, Germany
Electrons in quantum dots are confined in all three spatial directions. The confinement leads to a quantisation of the eigenenergy of the electron states. Semiconductor quantum dots are promising candidates for the realisation of quantum bits (qubits). Similar to a classical bit a qubit is based on two states, e.g. the charge state of a single electron in a tunnel coupled double quantum dot. In such a system the interaction with phonons is a major source of decoherence.
In order to investigate the electron-phonon coupling we employ phonon cavities that are nanoscale bridges excavated from an AlGaAs/GaAs heterostructure. The latter contains a two-dimensional electron system (2DES). By use of top gates we locally deplete the 2DEG and, thus, define a freely suspended quantum dot on the bridge. In this way we couple a phonon cavity with a charge cavity.
This setup allows the observation of coupled electro-mechanical modes [1]. The tunability of the modified phonon spectrum of the nanobridge will allow to investigate the electron-phonon interaction by means of transport experiments.
[1] E. M. Höhberger et al., PRL 92, 046804 (2004).