We demonstrate an original method based on controlled oxidation for creating high-quality tunnel junctions between superconducting Al reservoirs and InAs semiconductor nanowires (NWs). We show clean tunnel characteristics with a current suppression by >4 orders of magnitude for a junction bias well below the Al gap of $\Delta$0≈ 200 $\mu$eV. The experimental data agree well with the Bardeen--Cooper--Schrieffer theoretical expectations for a superconducting tunnel junction. The studied devices employ small-scale tunnel contacts functioning as thermometers as well as larger electrodes that provide proof-of-principle active cooling of the electron distribution in the NWs. A peak refrigeration of approximately $\delta$T = 10 mK is achieved at a bath temperature of $T_{bath}$ ≈ 250--350 mK for our prototype devices. This method introduces important perspectives for the investigation of the thermoelectric effects in semiconductor nanostructures and for nanoscale refrigeration.
Titolo: | InAs nanowire superconducting tunnel junctions: Quasiparticle spectroscopy, thermometry, and nanorefrigeration | |
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Data di pubblicazione: | 2017 | |
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Digital Object Identifier (DOI): | http://dx.doi.org/10.1007/s12274-017-1558-7 | |
Handle: | http://hdl.handle.net/11384/66905 | |
Appare nelle tipologie: | 1.1 Articolo in rivista |