Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 49: Poster Session: Superconductivity

TT 49.22: Poster

Mittwoch, 3. April 2019, 15:00–18:30, Poster D

Single-Channel Josephson Effect in a High-Transmission Atomic Contact — Jacob Senkpiel¹, •Simon Dambach², Markus Etzkorn¹, Robert Drost¹, Ciprian Padurariu², Björn Kubala², Wolfgang Belzig³, Alfredo Levy Yeyati⁴, Juan Carlos Cuevas⁴, Joachim Ankerhold², Christian R. Ast¹, and Klaus Kern^1,5 — ¹Max-Planck-Institut für Festkörperforschung, Germany — ²Institut für komplexe Quantensysteme, Universität Ulm, Germany — ³Fachbereich Physik, Universität Konstanz, Germany — ⁴Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Spain — ⁵Institut de Physique, École Polytechnique Fédérale de Lausanne, Switzerland

The Josephson effect in scanning tunneling microscopy is an excellent tool to probe the properties of the superconducting order parameter on a local scale through the Ambegaokar-Baratoff (AB) relation. Using single atomic contacts created by means of atom manipulation, we demonstrate that in the extreme case of a single transport channel through the atomic junction, modifications of the current-phase relation lead to significant deviations from the linear AB formula. Using the full current-phase relation for arbitrary transmission, we model the Josephson effect in the dynamical–Coulomb-blockade regime because the charging energy of the junction capacitance cannot be neglected. We find excellent agreement with the experimental data. Projecting the current-phase relation onto the charge-transfer operator shows that at high transmission multi–Cooper-pair tunneling processes may occur.
J. Senkpiel et al., arXiv:1810.10609.