论文标题
非局部超导量子干扰装置
Nonlocal superconducting quantum interference device
论文作者
论文摘要
超导量子干扰设备（鱿鱼）结合了两个超导体/绝缘体/超导体/超导体（SIS）Josephson连接处的封闭环形构成了当前可用的一些最敏感的磁场和电场探测器的核心。这些应用中的鱿鱼通常用有限的电压进行操作，该电压通过AC Josephson效应产生微波辐射。该辐射可能会影响正在测量的系统。我们在这里描述了一个鱿鱼，其中约瑟夫森连接是由正常金属（n）的条形成的，与超导体的电气接触良好。这样的SNS鱿鱼可以在有限的电压偏置下进行操作，性能比传统的SIS鱿鱼可比或可能更好。但是，它们还允许一种新型的操作模式，该模式基于约瑟夫森交界处正常金属中的准粒子电流和超电流的异常相互作用。该新方法允许测量SNS鱿鱼的临界电流的通量依赖性，而无需在SNS连接范围内应用有限的电压偏置，从而无需产生微波辐射即可实现敏感的通量检测。
Superconducting quantum interference devices (SQUIDs) that incorporate two superconductor/insulator/superconductor (SIS) Josephson junctions in a closed loop form the core of some of the most sensitive detectors of magnetic and electric fields currently available. SQUIDs in these applications are typically operated with a finite voltage which generates microwave radiation through the ac Josephson effect. This radiation may impact the system being measured. We describe here a SQUID in which the Josephson junctions are formed from strips of normal metal (N) in good electrical contact with the superconductor (S). Such SNS SQUIDs can be operated under a finite voltage bias with performance comparable or potentially better than conventional SIS SQUIDs. However, they also permit a novel mode of operation that is based on the unusual interplay of quasiparticle currents and supercurrents in the normal metal of the Josephson junction. The new method allows measurements of the flux dependence of the critical current of the SNS SQUID without applying a finite voltage bias across the SNS junction, enabling sensitive flux detection without generating microwave radiation.
