Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 3: Quantum Dots and Wires 1: Transport and Electronic Properties
HL 3.4: Vortrag
Montag, 5. September 2022, 10:30–10:45, H32
Wave-function mapping of excited quantum dot states — •Daniel Hecker1, Jens Kerski1, Nelson Creutzburg1, Arne Ludwig2, Andreas D. Wieck2, Martin Geller1, and Axel Lorke1 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen, Germany — 2Chair of Applied Solid State Physics, Ruhr-University Bochum, Germany
Self-assembled quantum dots (QDs) are promising candidates for quantum information technologies, quantum sensing and various electro-optical applications. They are often approximated as two-dimensional harmonic oscillators. Although this approximation of electron states in a harmonic oscillator is very successful, the influence of the electron-electron interaction on the excited few-particle wave-functions and their dynamics into equilibrium has not been studied in detail.
We investigate an ensemble of InAs/GaAs QDs, embedded in a high-electron-mobility transistor with a two-dimensional electron gas (2DEG) as conductive channel. By applying a gate voltage to the transistor, the QDs can be selectively occupied with electrons tunneling from the 2DEG, and the time-resolved transconductance of the 2DEG can be measured. A rate equation based evaluation of the transconductance allows us to determine the tunneling rates of the QD states. In combination with a magnetic field that tunes the wave function-dependent tunneling probability, this enables us to investigate the shape and dynamics of the (excited) few-electron states.