Single channel Josephson effect in a high transmission atomic contact

authored by: Jacob Senkpiel, Simon Dambach, Markus Etzkorn, Robert Drost, Ciprian Padurariu, Björn Kubala, Wolfgang Belzig, Alfredo Levy Yeyati, Juan Carlos Cuevas, Joachim Ankerhold, Christian R. Ast, Klaus Kern
Abstract: The Josephson effect in scanning tunneling microscopy (STM) is an excellent tool to probe the properties of a superconductor on a local scale. We use atomic manipulation in a low temperature STM to create mesoscopic single channel contacts and study the Josephson effect at arbitrary transmissions. We observe significant deviations from the Ambegaokar-Baratoff formula relating the critical current to the order parameter starting from transmissions of τ > 0.1. Using the full current-phase relation, we model the Josephson effect in the dynamical Coulomb blockade regime, where the charging energy of the junction capacitance cannot be neglected, and find excellent agreement with the experimental data. Projecting the current-phase relation onto the charge transfer operator shows that at high transmission, non-linear behaviour arises and multiple Cooper pair tunneling may occur. Our model includes these deviations, which become non-negligible in Josephson-STM, for example, when scanning across single adatoms.
External Organisation(s): Max Planck Institute for Solid State Research (MPI-FKF)
Ulm University
German Aerospace Center (DLR)
University of Konstanz
Universidad Autónoma de Madrid
École polytechnique fédérale de Lausanne (EPFL)
Type: Article
Journal: Communications Physics
Volume: 3
Publication date: 01.12.2020
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all)
Electronic version(s): https://doi.org/10.1038/s42005-020-00397-z (Access: Open)

BibTeX

@article{f027193e83b24dafa6d0fb77ea7c21fc,
title = "Single channel Josephson effect in a high transmission atomic contact",
abstract = "The Josephson effect in scanning tunneling microscopy (STM) is an excellent tool to probe the properties of a superconductor on a local scale. We use atomic manipulation in a low temperature STM to create mesoscopic single channel contacts and study the Josephson effect at arbitrary transmissions. We observe significant deviations from the Ambegaokar-Baratoff formula relating the critical current to the order parameter starting from transmissions of τ > 0.1. Using the full current-phase relation, we model the Josephson effect in the dynamical Coulomb blockade regime, where the charging energy of the junction capacitance cannot be neglected, and find excellent agreement with the experimental data. Projecting the current-phase relation onto the charge transfer operator shows that at high transmission, non-linear behaviour arises and multiple Cooper pair tunneling may occur. Our model includes these deviations, which become non-negligible in Josephson-STM, for example, when scanning across single adatoms.",
author = "Jacob Senkpiel and Simon Dambach and Markus Etzkorn and Robert Drost and Ciprian Padurariu and Bj{\"o}rn Kubala and Wolfgang Belzig and Yeyati, {Alfredo Levy} and Cuevas, {Juan Carlos} and Joachim Ankerhold and Ast, {Christian R.} and Klaus Kern",
note = "Funding information: We gratefully acknowledge fruitful discussions with Berthold J{\"a}ck and Elke Scheer. Funding from the European Research Council for the Consolidator Grant ABSOLUTE-SPIN (Grant No. 681164), from the Spanish MINECO (Grant No. FIS2014-55486-P, FIS2017-84057-P and FIS2017-84860-R), from the “Mar{\'i}a de Maeztu” Programme for Units of Excellence in R&D (MDM-2014-0377), from the Zeiss Foundation, from the DFG through AN336/11-1 and from the IQST is also gratefully acknowledged. J.C.C. and W.B. acknowledge support from the DFG through SFB 767.",
year = "2020",
month = dec,
day = "1",
doi = "10.1038/s42005-020-00397-z",
language = "English",
volume = "3",
journal = "Communications Physics",
publisher = "Springer Nature",
number = "1",
}