标题： 非均匀超导体中的超电流流动 显示英文标题

标题： Supercurrent flow in inhomogeneous superconductors

摘要： 我们研究了超导薄膜中的不均匀性如何改变超电流的流动模式。在临界温度附近工作，并假设在吉布斯-兰道泛函的二次项中存在短程无序模型，我们发展了一种关于不均匀性强度的微扰理论。通过将紫外发散吸收进临界温度的重整化中，我们得到了一个由大尺度物理所支配的定义明确的理论。在存在不均匀性的情况下，序参量和超电流的相关函数表现出长程幂律行为，这可以归因于振幅模和相位模的混合。随着平均电流的增加，涨落幅度增大，并且系统在临界电流附近变得强烈不均匀。非均匀的超流会产生随机磁场，其在薄NbN膜中的大小可能与地球磁场相当。我们讨论了使用SQUID-on-tip技术检测它的可行性。 显示英文摘要

摘要： We study how the supercurrent flow pattern is altered by inhomogeneities in superconducting films. Working in the vicinity of the critical temperature and assuming a model of short-range disorder in the quadratic term of the Ginzburg-Landau functional, we develop a perturbation theory in the inhomogeneity strength. Absorbing the ultraviolet divergences into the renormalization of the critical temperature, we arrive at a well-defined theory governed by large-scale physics. In the presence of inhomogeneities, the correlation functions of the order parameter and supercurrent exhibit a long-range power-law behavior, which can be attributed to the mixing of the amplitude and phase modes. The fluctuation magnitude grows with increasing the average current, and the system becomes strongly inhomogeneous near the critical current. An inhomogeneous superflow will generate a random magnetic field, whose magnitude in thin NbN films can be comparable to Earth's magnetic field. We discuss the feasibility of detecting it using the SQUID-on-tip technique.