Emergent Interfacial Superconductivity between Twisted Cuprate Superconductors

S. Y. Frank Zhao; Nicola Poccia; Xiaomeng Cui; Pavel A. Volkov; Hyobin Yoo; Rebecca Engelke; Yuval Ronen; Ruidan Zhong; Genda Gu; Stephan Plugge; Tarun Tummuru; Marcel Franz; Jedediah H. Pixley; Philip Kim

arXiv · 2108.13455

Emergent Interfacial Superconductivity between Twisted Cuprate Superconductors

S. Y. Frank Zhao·Nicola Poccia·Xiaomeng Cui·Pavel A. Volkov·Hyobin Yoo·Rebecca Engelke·Yuval Ronen·Ruidan Zhong·Genda Gu·Stephan Plugge·Tarun Tummuru·Marcel Franz·Jedediah H. Pixley·Philip Kim

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Abstract

Twisted interfaces between stacked van der Waals cuprate crystals enable tunable Josephson coupling between in-plane anisotropic superconducting order parameters. Employing a novel cryogenic assembly technique, we fabricate Josephson junctions with an atomically sharp twisted interface between Bi2Sr2CaCu2O8+x crystals. The Josephson critical current density sensitively depends on the twist angle, reaching the maximum value comparable to that of the intrinsic junctions at small twisting angles, and is suppressed by almost 2 orders of magnitude yet remains finite close to 45 degree twist angle. Through the observation of fractional Shapiro steps and the analysis of Fraunhofer patterns we show that the remaining superconducting coherence near 45 degree is due to the co-tunneling of Cooper pairs, a necessary ingredient for high-temperature topological superconductivity.

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S. Y. Frank Zhao, Nicola Poccia, Xiaomeng Cui, Pavel A. Volkov, Hyobin Yoo, Rebecca Engelke, Yuval Ronen, Ruidan Zhong, Genda Gu, Stephan Plugge, Tarun Tummuru, Marcel Franz, Jedediah H. Pixley, Philip Kim. 2021-08-30. Emergent Interfacial Superconductivity between Twisted Cuprate Superconductors. https://arxiv.org/abs/2108.13455

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