Dresden 2020 – wissenschaftliches Programm
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TT 55.11: Vortrag
Donnerstag, 19. März 2020, 12:30–12:45, HSZ 204
Optimized proximity thermometer for ultra-sensitive detection — Bayan Karimi1, •Danilo Nikolic2, Tuomas Tuukkanen1, Joonas T. Peltonen1, Wolfgang Belzig2, and Jukka P. Pekola1 — 1QuESTech and QTF Centre of Excellence, Department of Applied Physics, Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland — 2QuESTech and Fachbereich Physik, Universität Konstanz, D-78467, Germany
Due to its importance for understanding the quantum principles of nature as well as technological development, the possibility of measuring low temperatures has drawn attention over decades. We present a set of experiments to optimize the performance of the noninvasive thermometer based on proximity superconductivity. Current through a standard tunnel junction between an aluminum superconductor and a copper electrode is controlled by the strength of the proximity induced to this normal metal, which in turn is determined by the position of direct superconducting contact from the tunnel junction. Several devices with different distances were tested. We develop a theoretical model based on the Usadel equations and dynamic Coulomb blockade which reproduces the measured results and yields a tool to calibrate the thermometer and to optimize it further in future experiments. This project has received funding from the EU Horizon 2020 program (Marie Sklodowska-Curie action QuesTech 766025).  B.Karimi, D.Nikolic, T.Tuukkanen, J.T.Peltonen, W.Belzig, and J.P.Pekola, arXiv:1911.02844 [cond-mat.mes-hall] (2019).