NbN纳米环中的几何超导二极管效应
Geometric Superconducting Diode Effect in an NbN Nanoring
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中文总结 AI 辅助
研究在NbN纳米环中实现几何诱导超导二极管效应，通过不对称几何结构引入反演对称性破缺，器件有明显极性可切换的临界电流非互易性，测量揭示其磁场和温度依赖性，为非互易超导传输研究及超导电子学提供平台与设计原则。
中文摘要 AI 辅助
超导二极管具有非互易临界电流，是低功耗低温电子学和超导电路的理想构建模块。现有超导二极管平台通常依赖约瑟夫森结、多层异质结构、铁磁元件、栅极定义结构。本文展示了在结构简单的单材料NbN纳米环中实现的几何诱导超导二极管效应，其中仅通过不对称几何结构引入反演对称性破缺。该器件表现出明显且极性可切换的临界电流非互易性。系统的磁场和温度相关测量表明，在低场下，施加的磁场在相反偏置方向之间不对称地重新分配临界电流，而不会显著降低整体超导载流能力。此外，最大非互易性和二极管效率表现出不同的温度依赖性：最大二极管效率跟随能隙的演变，而最大非互易性与超流密度更密切相关。这些结果将不对称超导纳米环确立为研究非互易超导传输的最小几何平台，并为未来超导电子学提供了简单的设计原则。
英文摘要
Superconducting diodes, which exhibit nonreciprocal critical currents, are promising building blocks for low-power cryogenic electronics and superconducting circuits. Existing superconducting diode platforms commonly rely on Josephson junctions, multilayer heterostructures, ferromagnetic elements, gate-difined structures. Here, we demonstrate a geometrically induced superconducting diode effect realized in a structurally minimal, single-materials NbN nanoring, where inversion-symmetry breaking is introduced solely by the asymmetric geometry. The device exhibits pronounced and polarity-switchable critical-current nonreciprocity. Systematic magnetic-field and temperature-dependent measurements reveal that, at low fields, the applied magnetic field redistributes the critical current asymmetrically between opposite bias directions without significantly reducing the overall superconducting current-carrying capability. Moreover, the maximal nonreciprocity and diode efficiency exhibit distinct temperature dependence: the maximal diode efficiency follows the evolution of the energy gap, whereas the maximal nonreciprocity is more closely associated with the superfluid density. These results establish asymmetric superconducting nanorings as a minimal geometric platform for studying nonreciprocal superconducting transport and provide a simple design principle for future superconducting electronics.
