Yabuki Naoto, Moriya Rai, Arai Miho, Sata Yohta, Morikawa Sei, Masubuchi Satoru, Machida Tomoki
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.
Nat Commun. 2016 Feb 2;7:10616. doi: 10.1038/ncomms10616.
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.
在具有不同序参量的两个超导体之间的超电流流动，即所谓的约瑟夫森效应，可以通过在两个超导体之间插入非超导材料来解耦它们的波函数来实现。这些约瑟夫森结已应用于从数字电子到量子电子等领域，但其功能受到界面质量和非超导材料使用的限制。在这里，我们表明，通过剥离层状二硫属化物（NbSe2）超导体，解理表面之间的范德华（vdW）接触反而可以用于构建约瑟夫森结。这得益于范德华异质结构技术的最新进展，通过在结制备过程中消除所有热处理，实现了无氧化和相互扩散的原子级平整范德华界面。在这里，我们证明了这种人工创建的范德华界面为两个NbSe2晶体的波函数提供了足够的解耦，范德华约瑟夫森结表现出高超电流透明度。
