Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 33: TR: Nanoelectronics I: Quantum Dots, Wires, Point Contacts 2
TT 33.6: Vortrag
Donnerstag, 25. März 2010, 15:15–15:30, H19
High frequency pulsed-gate technique for the measurement of tunneling and relaxation rates in coupled quantum dots — •Daniel Harbusch1, Stephan Manus1, Peter Tranitz2, Werner Wegscheider3, and Stefan Ludwig1 — 1Fakultät für Physik, Ludwig-Maximilians-Universität München, München, Germany — 2Institut für Experimentelle Physik, Universität Regensburg, Regensburg, Germany — 3Laboratory for Solid State Physics, ETH Zürich, Zürich, Switzerland
Tunneling frequencies and charge relaxation rates in a double quantum dot (QD) are directly probed by pulsing control gates of the double QD and measuring average charge occupations using a nearby quantum point contact (QPC) as detector.
Our nano-devices are electrostatically defined in the two-dimensional electron system of a GaAs/AlGaAs heterostructure. All measurements are performed at an electron temperature about T ≈ 100 mK.
Our broadband sample holder is based on impedance matched micro strip lines optimized for pulsed gate experiments, covering the large bandwidth from dc to 18 GHz. We pulse individual gates of a double or triple QD occupied with only few electrons at pulse widths down to 150 ps and demonstrate a variety of applications. We directly measure tunneling and energy relaxation rates. Our results show the suitability of the setup for future experiments on the coherent charge transport of single electrons in a triple QD.