Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 33: Superconductivity, Measuring Devices, Matter at Low Temperature: Poster Session
TT 33.51: Poster
Mittwoch, 28. März 2012, 15:00–19:00, Poster B
Mesoscopic conductance and critical current fluctuations in Nb/InAs-nanowire/Nb Josephson Junctions — Yusuf H. Günel1,2, •Igor Batov3, Hilde Hardtdegen1,2, Kamil Sladek1,2, Andreas Winden1,2, Karl Weis1,2, Gregor Panaitov4,2, Detlev Grützmacher1,2, and Thomas Schäpers1,2,5 — 1Peter Grünberg Institut (PGI-9), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — 2JARA - Fundamentals of Future Information Technology — 3Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, 142432 Moscow district, Russia — 4Peter Grünberg Institut (PGI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — 5II. Physikalisches Institut, RWTH Aachen, 52056 Aachen, Germany
We report on the experimental study of mesoscopic Josephson junctions based on InAs nanowires and niobium superconducting electrodes. The gate voltage and magnetic field dependent measurements revealed pronounced conductance and critical current fluctuations. We found that the pattern of the conductance fluctuations as a function of gate voltage follows precisely the fluctuations of the Josephson critical current. It has been found that the conductance fluctuation amplitude in Nb/InAs-nanowire/Nb samples significantly exceeds the amplitude of the normal-state universal conductance fluctuations (UCF) in the reference samples with normal conducting Au/Ti contacts. We attribute the enhancement of the conductance fluctuations in nanowires contacted with superconductors to the contribution of phase-coherent Andreev reflection.