Giant thermoelectric effects in a proximity-coupled superconductor-ferromagnet device

Peter Machon, Matthias Eschrig, Wolfgang Belzig

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Abstract

The usually negligibly small thermoelectric effects in superconducting
heterostructures can be boosted dramatically due to the simultaneous effect of spin splitting and spin filtering. Building on an idea of our earlier work (Machon et al 2013 Phys. Rev. Lett. 110 047002), we propose realistic mesoscopic setups to observe thermoelectric effects in superconductor heterostructures with ferromagnetic interfaces or terminals. We focus on the Seebeck effect being a direct measure of the local thermoelectric response and nd that a thermopower of the order of ~250 μV/K can be achieved in a transistor-like structure, in which a third terminal allows to drain the thermal current. A measurement of the thermopower can furthermore be used to determine quantitatively the spin-dependent interface parameters that induce the spin splitting. For applications in nanoscale cooling we discuss the figure of merit for which we find values exceeding 1.5 for temperatures of ≤ 1K.
Original languageEnglish
Article number073002
Number of pages19
JournalNew Journal of Physics
Volume16
DOIs
Publication statusPublished - 2 Jul 2014

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