Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 34: Superconductivity: Heterostructures
TT 34.2: Vortrag
Dienstag, 1. April 2014, 11:45–12:00, HSZ 201
Giant thermoelectric effects in proximity-coupled superconductor-ferromagnet devices — •Peter Machon1, Matthias Eschrig2, and Wolfgang Belzig1 — 1Department of Physics, University of Konstanz, D-78457 Konstanz, Germany — 2SEPnet and Hubbard Theory Consortium, Department of Physics, Royal Holloway,
University of London, Egham, Surrey TW20 0EX, United Kingdom
The usually negligibly small thermoelectric effects in superconducting heterostructures can be boosted dramatically due to the simultaneous effect of spin-dependent scattering and spin-filtering [Phys. Rev. Lett. 110, 047002 (2013)]. Using that principle, we propose realistic setups to measure the local thermoelectric effects combining superconducting and ferromagnetic elements. We find that a thermopower ∼100µ V/K can be achieved if the setup allows to drain the thermal current. For applications in nano-cooling we show that the figure of merit can exceed one for realistic parameters at low temperatures.
Due to crossed Andreev reflections and coherent electron transfer, three terminal structures also provide nonlocal thermoelectricity, here discussed in clean and in disordered structures. Our results show that a nonlocal version of the Onsager’s reciprocity relation holds in a three terminal quantum coherent device.