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TT: Fachverband Tiefe Temperaturen
TT 33: TR: Nanoelectronics I: Quantum Dots, Wires, Point Contacts 2
TT 33.9: Talk
Thursday, March 25, 2010, 16:15–16:30, H19
Thermopower of a Cooper pair splitter — •Jens Siewert1,2 and Evgeny Ya. Sherman1,2 — 1Departamento de Química Física, Universidad del País Vasco , Apdo. 644, 48080 Bilbao, Spain — 2Ikerbasque, Basque Foundation for Science, Alameda Urquijo 36, 48011 Bilbao, Spain
A Cooper pair splitting device has been realized recently by connecting two quantum dots (formed by InAs nanowires [1] and single-wall carbon nanotubes [2]) to a single superconducting source electrode and two normal-conducting drain electrodes. The electrostatic potentials of the dots can be tuned by means of gate voltages. The dominant transport process at low temperatures and bias voltages is coherent Cooper-pair tunneling (’Andreev tunneling’). We study transport in this device at finite temperatures in the framework of a simple tunneling Hamiltonian model taking into account an extra tunneling term between the two quantum dots and possible asymmetries between the tunneling rates to the leads. We calculate the thermopower and address the question whether it provides a possibility to experimentally access the contribution of the crossed Andreev reflection process.
[1] L. Hofstetter, S. Csonka, J. Nygard, and C. Schönenberger, Nature 461, 960 (2009).
[2] L.G. Herrmann, F. Portier, P. Roche, A. Levy Yeyati, T. Kontos, and C. Strunk, e-print arxiv0909.3243 (2009).