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arXiv · 2303.16029

Twisted cuprate van der Waals heterostructures with controlled Josephson coupling

Mickey Martini·Yejin Lee·Tommaso Confalone·Sanaz Shokri·Christian N. Saggau·Daniel Wolf·Genda Gu·Kenji Watanabe·Takashi Taniguchi·Domenico Montemurro·Valerii M. Vinokur·Kornelius Nielsch·Nicola Poccia
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Abstract

Twisted van der Waals (vdW) heterostructures offer a unique platform for engineering the efficient Josephson coupling between cuprate thin crystals harboring the nodal superconducting order parameter. Preparing vdW heterostructures-based Josephson junction comprising stacked cuprates requires maintaining an ordered interface with preserved surface superconductivity. Here, we report the preparation of the Josephson junction out of the stacked Bi2Sr2CuCa2O8+d crystals using the cryogenic dry transfer technique and encapsulating the junction with an insulating layer, that protects the interface during the electrical contacts evaporation at the 10-6 mbar base pressure. We find that the Josephson critical current Ic has a maximum at low twist angles, comparable to that of the bulk intrinsic Josephson junctions, and is reduced by two orders of magnitude at twist angles close to 45°. The reduction of Ic occurs due to a mismatch between superconducting d-wave order parameters, which suppresses the direct Cooper pair tunneling.

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Mickey Martini, Yejin Lee, Tommaso Confalone, Sanaz Shokri, Christian N. Saggau, Daniel Wolf, Genda Gu, Kenji Watanabe, Takashi Taniguchi, Domenico Montemurro, Valerii M. Vinokur, Kornelius Nielsch, Nicola Poccia. 2024-02-11. Twisted cuprate van der Waals heterostructures with controlled Josephson coupling. https://doi.org/10.1016/j.mattod.2023.06.007

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