Abstract

We study the effects of random \(\pi \) Josephson junctions and applied magnetic field on the quantum phase transitions of superconducting arrays, described by a two-dimensional phase-glass model. The zero-temperature phase diagram and critical behavior are obtained from path-integral Monte Carlo simulations. A superconducting chiral-glass phase occurs for sufficiently large disorder resulting from frustration effects of the \(\pi \) junctions. Unlike the superconductor–insulator transition for weak disorder, the chiral-glass to insulator transition is insensitive to additional frustration introduced by an external magnetic field corresponding to half flux quantum per plaquette. The results are consistent with recent measurements on superconducting thin films with a periodic pattern of nanoholes in an applied magnetic field and doped with magnetic impurities. The magnetic-field frustration effects for the activation energy at low doping and its disappearance at higher doping, observed experimentally, is indicative of a transition to the chiral-glass regime.

Graphic abstract

中文翻译：

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具有随机 $$\pi $$ π 结的超导阵列中的磁场挫败和手性玻璃到绝缘体的转变

摘要

我们研究了随机\(\pi \)约瑟夫森结和外加磁场对超导阵列量子相变的影响，由二维相玻璃模型描述。零温度相图和临界行为是从路径积分蒙特卡罗模拟中获得的。由于\(\pi \) 的挫败效应引起的足够大的无序会发生超导手性玻璃相路口。与弱无序的超导体 - 绝缘体转变不同，手性玻璃到绝缘体的转变对外部磁场引入的额外挫折不敏感，该外部磁场对应于每个小块的半通量量子。结果与最近对在外加磁场中具有纳米孔周期性图案并掺杂有磁性杂质的超导薄膜进行的测量一致。实验观察到，低掺杂时激活能的磁场抑制效应及其在高掺杂时的消失表明向手性玻璃状态的转变。

图形摘要