Critical current fluctuations in graphene Josephson junctions

Abstract We have studied 1/f noise in critical current $$I_c$$ 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 $$\simeq 5$$ ≃ 5 nA. The low frequency noise in th...

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Autores principales:	Mohammad T. Haque, Marco Will, Matti Tomi, Preeti Pandey, Manohar Kumar, Felix Schmidt, Kenji Watanabe, Takashi Taniguchi, Romain Danneau, Gary Steele, Pertti Hakonen
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/7a7bb27580b64372a25dda797d381d36
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spelling	oai:doaj.org-article:7a7bb27580b64372a25dda797d381d362021-12-02T18:01:40ZCritical current fluctuations in graphene Josephson junctions10.1038/s41598-021-99398-32045-2322https://doaj.org/article/7a7bb27580b64372a25dda797d381d362021-10-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-99398-3https://doaj.org/toc/2045-2322Abstract We have studied 1/f noise in critical current $$I_c$$ 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 $$\simeq 5$$ ≃ 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 $$v_{rf}$$ v rf at 600–650 MHz. We find 1/f critical current fluctuations on the order of $$\delta I_c/I_c \simeq 10^{-3}$$ δ I c / I c ≃ 10 - 3 per unit band at 1 Hz. The noise power spectrum of critical current fluctuations $$S_{I_c}$$ S I c measured near the Dirac point at large, sub-critical rf-carrier amplitudes obeys the law $$S_{I_c}/{I{_c}}^2 = a/f^{\beta }$$ S I c / I c 2 = a / f β where $$a\simeq 4\times 10^{-6}$$ a ≃ 4 × 10 - 6 and $$\beta \simeq 1$$ β ≃ 1 at $$f > 0.1$$ f > 0.1 Hz. Our results point towards significant fluctuations in $$I_c$$ I c originating from variation of the proximity induced gap in the graphene junction.Mohammad T. HaqueMarco WillMatti TomiPreeti PandeyManohar KumarFelix SchmidtKenji WatanabeTakashi TaniguchiRomain DanneauGary SteelePertti HakonenNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-10 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Mohammad T. Haque Marco Will Matti Tomi Preeti Pandey Manohar Kumar Felix Schmidt Kenji Watanabe Takashi Taniguchi Romain Danneau Gary Steele Pertti Hakonen Critical current fluctuations in graphene Josephson junctions
description	Abstract We have studied 1/f noise in critical current $$I_c$$ 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 $$\simeq 5$$ ≃ 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 $$v_{rf}$$ v rf at 600–650 MHz. We find 1/f critical current fluctuations on the order of $$\delta I_c/I_c \simeq 10^{-3}$$ δ I c / I c ≃ 10 - 3 per unit band at 1 Hz. The noise power spectrum of critical current fluctuations $$S_{I_c}$$ S I c measured near the Dirac point at large, sub-critical rf-carrier amplitudes obeys the law $$S_{I_c}/{I{_c}}^2 = a/f^{\beta }$$ S I c / I c 2 = a / f β where $$a\simeq 4\times 10^{-6}$$ a ≃ 4 × 10 - 6 and $$\beta \simeq 1$$ β ≃ 1 at $$f > 0.1$$ f > 0.1 Hz. Our results point towards significant fluctuations in $$I_c$$ I c originating from variation of the proximity induced gap in the graphene junction.
format	article
author	Mohammad T. Haque Marco Will Matti Tomi Preeti Pandey Manohar Kumar Felix Schmidt Kenji Watanabe Takashi Taniguchi Romain Danneau Gary Steele Pertti Hakonen
author_facet	Mohammad T. Haque Marco Will Matti Tomi Preeti Pandey Manohar Kumar Felix Schmidt Kenji Watanabe Takashi Taniguchi Romain Danneau Gary Steele Pertti Hakonen
author_sort	Mohammad T. Haque
title	Critical current fluctuations in graphene Josephson junctions
title_short	Critical current fluctuations in graphene Josephson junctions
title_full	Critical current fluctuations in graphene Josephson junctions
title_fullStr	Critical current fluctuations in graphene Josephson junctions
title_full_unstemmed	Critical current fluctuations in graphene Josephson junctions
title_sort	critical current fluctuations in graphene josephson junctions
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/7a7bb27580b64372a25dda797d381d36
work_keys_str_mv	AT mohammadthaque criticalcurrentfluctuationsingraphenejosephsonjunctions AT marcowill criticalcurrentfluctuationsingraphenejosephsonjunctions AT mattitomi criticalcurrentfluctuationsingraphenejosephsonjunctions AT preetipandey criticalcurrentfluctuationsingraphenejosephsonjunctions AT manoharkumar criticalcurrentfluctuationsingraphenejosephsonjunctions AT felixschmidt criticalcurrentfluctuationsingraphenejosephsonjunctions AT kenjiwatanabe criticalcurrentfluctuationsingraphenejosephsonjunctions AT takashitaniguchi criticalcurrentfluctuationsingraphenejosephsonjunctions AT romaindanneau criticalcurrentfluctuationsingraphenejosephsonjunctions AT garysteele criticalcurrentfluctuationsingraphenejosephsonjunctions AT perttihakonen criticalcurrentfluctuationsingraphenejosephsonjunctions
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Critical current fluctuations in graphene Josephson junctions

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