Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 84: Quantum Dots and Wires: Transport Properties III (mainly Thermal Gradients)
HL 84.4: Vortrag
Donnerstag, 29. März 2012, 15:45–16:00, EW 202
Thermopower of a Coupled Quantum Dot System — •Holger Thierschmann1, Michael Henke1, Johannes Knorr1, Wolfgang Hansen2, Hartmut Buhmann1, and Laurens W. Molenkamp1 — 1Physikalisches Institut (Experimentelle Physik III), Universität Würzburg, Germany — 2Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Germany
We perform electrical characterization and thermopower measurements on lateral gate patterned coupled quantum dot systems based on a GaAs/AlGaAs HEMT structure. The two quantum dots are connected in series and are tuned into the strong coupling regime. A temperature difference of a few 10mK is established using the current heating technique [1]. We observe strong asymmetries in the thermovoltage signal around the tripel points, which we can explain within an electrostatic capacitance model and also between two tripel points, which we believe are caused by molecular-like electron states. Due to strong interdot tunnel coupling we find thermovoltages in regions with finite conductance, which is in strong contrast to the thermopower of a single quantum dot [2]. [1] R. Scheibner, H. Buhmann, D. Reuter, M. N. Kiselev and L.W. Molenkamp, PRL 95, 176602 (2005). [2] R. Scheibner, E.G. Novik, T. Borzenko, M. König, D. Reuter, A.D. Wieck, H. Buhmann and L.W. Molenkamp, Phys. Rev. B 75, 041301(R) (2007).