Quantum phase slip (QPS) is an important effect that occurs in one-dimensional (1D) or quasi-1D superconducting (SC) materials. Due to the extremely high requirements on the uniformity and quality of SC nanowires, it is currently very challenging to obtain repeatable and controllable QPS devices. Here, we report a systematic study of the QPS effect in NbN SC nanowires. High-quality NbN nanowires with different widths are fabricated by combining the processes of photo-lithography, electron beam lithography, and inductively coupled plasma etching. It is found that the electrical transport of the nanowires showed a systematic variation with the wire width, and a clear evolution from single to multiple QPS events with the decrease in wire width is uncovered at low temperatures. Based on these experimental results, the phase diagram reflecting the evolution of the physical states of the nanowires with wire width and temperature is obtained. In addition, we observed the features of the critical voltage, which is a characteristic of the occurrence of coherent QPS (cQPS), in samples with a width of 36 nm in the multiple QPS region. It is worth noting that this cQPS behavior was detected in a non-high-impedance environment.

中文翻译：

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NbN 纳米线中相滑差随线宽的演变以及无高阻抗环境下临界电压特征的观察

量子相滑（QPS）是一维（1D）或准1D超导（SC）材料中发生的重要效应。由于SC纳米线的均匀性和质量要求极高，目前获得可重复、可控的QPS器件非常具有挑战性。在这里，我们报告了 NbN SC 纳米线 QPS 效应的系统研究。通过光刻、电子束光刻和电感耦合等离子体刻蚀工艺相结合，制备出不同宽度的高质量NbN纳米线。研究发现，纳米线的电传输随着线宽的变化而呈现出系统性的变化，并且在低温下，随着线宽的减小，从单个 QPS 事件到多个 QPS 事件的明显演变被发现。基于这些实验结果，获得了反映纳米线物理状态随线宽和温度演变的相图。此外，我们在多重QPS区域中宽度为36 nm的样品中观察到临界电压的特征，这是相干QPS（cQPS）发生的特征。值得注意的是，这种 cQPS 行为是在非高阻抗环境中检测到的。