SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 20: Superconductivity: Tunnelling and Josephson Junctions

TT 20.13: Vortrag

Dienstag, 28. März 2023, 12:45–13:00, HSZ 103

Tracking current path in multi-terminal graphene Josephson junctions — •Devang Parmar¹, Rainer Kraft², Preeti Pandey³, Ralph Krupke^1,4,5, and Romain Danneau¹ — ¹Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Karlsruhe D-76021, Germany — ²Institute of Physics, Karlsruhe Institute of Technology, Karlsruhe D-76049, Germany — ³Low Temperature Laboratory, QTF Centre of Excellence, Department of Applied Physics, Aalto University School of Science, P.O. Box 15100, 00076 Aalto, Finland — ⁴Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe D-76021, Germany — ⁵Department of Materials and Earth Sciences, Technical University Darmstadt, Darmstadt 64287, Germany

Multiterminal Josephson junctions have been predicted to be platforms to observe various exotic phenomena such as new topological phases of matter [1], correlated states [2-5] or the so-called Andreev molecules [6,7]. In order to control the electronic properties of these complex devices, it is important to comprehend and track the supercurrent flow with respect to their geometries and superconducting lead peculiarities.

Here, we investigated the supercurrent in multi-terminal superconductor-graphene-superconductor (SGS) junctions. Together with magnetic interferometry experiments in these multiterminal graphene devices, we clearly observe that the contact transparencies can be very different from one lead to the other which mainly drives the entire transport properties in SGS. Our work provides insights of the supercurrent flow in multiterminal Josephson junctions and paves the way for further investigations in more complex multiterminal devices.

[1] R. P. Riwar et al., Nat Commun 7, 11167 (2016)

[2] A. Freyn et al., Phys. Rev. Lett. 106, 257005 (2011)

[3] A. H. Pfeffer et al., Phys. Rev. B 90, 075401 (2014)

[4] R. Mélin et al., Phys. Rev. B 100, 035450 (2019)

[5] K.-F. Huang et al., arXiv preprint arXiv:2008.03419 (2020)

[6] Z. Su et al., Nat. Commun. 8, 585 (2017)

[7] J.-D. Pillet et al., Nano Lett. 19, 7138 (2019)