Department of Physics, CNAM, University of Maryland, College Park, Maryland 20742, USA.
Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742, USA.
Phys Rev E. 2017 May;95(5-1):050201. doi: 10.1103/PhysRevE.95.050201. Epub 2017 May 30.
Through experiments and numerical simulations we explore the behavior of rf SQUID (radio frequency superconducting quantum interference device) metamaterials, which show extreme tunability and nonlinearity. The emergent electromagnetic properties of this metamaterial are sensitive to the degree of coherent response of the driven interacting SQUIDs. Coherence suffers in the presence of disorder, which is experimentally found to be mainly due to a dc flux gradient. We demonstrate methods to recover the coherence, specifically by varying the coupling between the SQUID meta-atoms and increasing the temperature or the amplitude of the applied rf flux.
通过实验和数值模拟，我们研究了射频超导量子干涉器件（rf SQUID）超材料的行为，这些超材料表现出了极端的可调谐性和非线性。这种超材料的新兴电磁特性对驱动相互作用的 SQUIDs 的相干响应程度敏感。相干性在存在无序的情况下会受到影响，实验发现这种无序主要是由于直流通量梯度。我们展示了恢复相干性的方法，特别是通过改变 SQUID 元原子之间的耦合以及增加温度或施加的射频通量的幅度。
