Kudriashov Andrei, Zhou Xiangyu, Hovhannisyan Razmik A, Frolov Alexander S, Elesin Leonid, Wang Yi Bo, Zharkova Ekaterina V, Taniguchi Takashi, Watanabe Kenji, Liu Zheng, Novoselov Kostya S, Yashina Lada V, Zhou Xin, Bandurin Denis A
Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore.
Institute for Functional Intelligent Materials, National University of Singapore, Singapore, Singapore.
Sci Adv. 2025 Jun 13;11(24):eadw6925. doi: 10.1126/sciadv.adw6925.
Josephson junctions (JJs) are key to superconducting quantum technologies and the search for self-conjugate quasiparticles potentially useful for fault-tolerant quantum computing. In topological insulator (TI)-based JJs, measuring the current-phase relation (CPR) can reveal unconventional effects such as Majorana bound states (MBS) and nonreciprocal transport. However, reconstructing CPR as a function of magnetic field has not been attempted. Here, we present a platform for field-dependent CPR measurements in planar JJs made of NbSe and few-layer BiSe. When a flux quantum [Formula: see text] threads the junction, we observe anomalous peak-dip CPR structure and nonreciprocal supercurrent flow. We show that these arise from a nonuniform supercurrent distribution that also leads to a robust and tunable Josephson diode effect. Furthermore, despite numerous previous studies, we find no evidence of MBS. Our results establish magnetic field-dependent CPR as a powerful probe of TI-based superconducting devices and offer design strategies for nonreciprocal superconducting electronics.
约瑟夫森结（JJs）是超导量子技术以及寻找可能对容错量子计算有用的自共轭准粒子的关键。在基于拓扑绝缘体（TI）的约瑟夫森结中，测量电流 - 相位关系（CPR）可以揭示非常规效应，如马约拉纳束缚态（MBS）和非互易输运。然而，尚未有人尝试将CPR重构为磁场的函数。在此，我们展示了一个用于在由NbSe和少层BiSe制成的平面约瑟夫森结中进行磁场依赖CPR测量的平台。当一个磁通量子[公式：见原文]穿过结时，我们观察到异常的峰 - 谷CPR结构和非互易超电流流动。我们表明，这些现象源于不均匀的超电流分布，这也导致了一种稳健且可调谐的约瑟夫森二极管效应。此外，尽管之前有大量研究，但我们未发现马约拉纳束缚态的证据。我们的结果将磁场依赖CPR确立为基于拓扑绝缘体的超导器件的有力探针，并为非互易超导电子学提供了设计策略。
