title: Supercurrent in van der Waals Josephson junction.
abstract: Supercurrent flow between two superconductors with different order parameters, a phenomenon known as the Josephson effect, can be achieved by inserting a non-superconducting material between two superconductors to decouple their wavefunctions. These Josephson junctions have been employed in fields ranging from digital to quantum electronics, yet their functionality is limited by the interface quality and use of non-superconducting material. Here we show that by exfoliating a layered dichalcogenide (NbSe2) superconductor, the van der Waals (vdW) contact between the cleaved surfaces can instead be used to construct a Josephson junction. This is made possible by recent advances in vdW heterostructure technology, with an atomically flat vdW interface free of oxidation and inter-diffusion achieved by eliminating all heat treatment during junction preparation. Here we demonstrate that this artificially created vdW interface provides sufficient decoupling of the wavefunctions of the two NbSe2 crystals, with the vdW Josephson junction exhibiting a high supercurrent transparency.
authors.affiliation: Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Yabuki
authors.affiliation: Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.
authors.forename: Rai
authors.identifier: http://orcid.org/0000-0001-7471-7432
authors.initials: R
authors.lastname: Moriya
authors.affiliation: Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Arai
authors.affiliation: Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.
authors.forename: Yohta
authors.initials: Y
authors.lastname: Sata
authors.affiliation: Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.
authors.forename: Sei
authors.initials: S
authors.lastname: Morikawa
authors.affiliation: Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Masubuchi
authors.affiliation: Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.|Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Machida
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