Wang Yue, Chen Lei, Pan Yinping, Zhang Denghui, Yu Shujie, Wu Guangting, Liu Xiaoyu, Wu Ling, Shi Weifeng, Zhang Guofeng, Zhang Lu, Peng Wei, Ren Jie, Wang Zhen
National Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, People's Republic of China.
University of the Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
ACS Nano. 2023 Aug 22;17(16):15466-15473. doi: 10.1021/acsnano.3c01301. Epub 2023 Aug 13.
The nanobridge junction (NBJ) is a type of Josephson junction that is advantageous for the miniaturization of superconducting circuits. However, the current-phase relation (CPR) of the NBJ usually deviates from a sinusoidal function, which has been explained by a simplified model with correlation only to its effective length. Here, we investigated both measured and calculated CPRs of niobium NBJs of a cuboidal shape with a three-dimensional bank structure. From a sine-wave to a sawtooth-like form, we showed that deviated CPRs of NBJs can be described quantitatively by its skewness Δθ. Furthermore, the measured dependence of Δθ on the critical current from 108 NBJs turned out to be consistent with the calculated dependence derived from the change in geometric dimensions. This suggested that the CPRs of NBJs can be tuned by their geometric dimensions. In addition, the calculated scaling behavior of Δ versus in 3D space was provided for the future design of superconducting circuits of a high integration level by using niobium NBJs.
纳米桥结（NBJ）是一种约瑟夫森结，有利于超导电路的小型化。然而，NBJ的电流-相位关系（CPR）通常偏离正弦函数，这已由一个仅与其有效长度相关的简化模型进行了解释。在此，我们研究了具有三维库结构的立方体形铌NBJ的测量和计算CPR。从正弦波到锯齿状形式，我们表明NBJ的偏离CPR可以通过其偏斜度Δθ进行定量描述。此外，从108个NBJ测量得到的Δθ对临界电流的依赖性结果与从几何尺寸变化得出的计算依赖性一致。这表明NBJ的CPR可以通过其几何尺寸进行调节。此外，还给出了在三维空间中Δ与的计算缩放行为，以便未来利用铌NBJ设计高集成度的超导电路。
