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Critical current fluctuations in graphene Josephson junctions

Haque, M. T.; Will, M.; Tomi, M.; Pandey, P.; Kumar, M.; Schmidt, F.; Watanabe, K.; Taniguchi, T.; Danneau, R.; Steele, G.; Hakonen, P.

We have studied 1/f noise in critical current I$_{c}$ in h-BN encapsulated monolayer graphene contacted by NbTiN electrodes. The sample is close to diffusive limit and the switching supercurrent with hysteresis at Dirac point amounts to ≃5 nA. The low frequency noise in the superconducting state is measured by tracking the variation in magnitude and phase of a reflection carrier signal v$_{rf}$ at 600–650 MHz. We find 1/f critical current fluctuations on the order of δI$_{c}$/I$_{c}$≃10$^{-3}$ per unit band at 1 Hz. The noise power spectrum of critical current fluctuations SI$_{c}$ measured near the Dirac point at large, sub-critical rf-carrier amplitudes obeys the law SI$_{c}$/I$_{c}$$^{2}$=a/f$^{ß}$ where a≃4×10$^{-6}$ and β≃1 at f>0.1 Hz. Our results point towards significant fluctuations in I$^{c}$ originating from variation of the proximity induced gap in the graphene junction.

Verlagsausgabe §
DOI: 10.5445/IR/1000139165
Veröffentlicht am 19.10.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Quantenmaterialien und -technologien (IQMT)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 2045-2322
KITopen-ID: 1000139165
HGF-Programm 47.11.05 (POF IV, LK 01) Towards Quantum and Neuromorphic Computing Functionalities
Erschienen in Scientific Reports
Verlag Nature Research
Band 11
Heft 1
Seiten Art.Nr. 19900
Vorab online veröffentlicht am 06.10.2021
Nachgewiesen in Scopus
Web of Science
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