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arXiv 2203.08587cond-mat.mes-hallcond-mat.supr-con
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平面约瑟夫森结中超导电流分布的扫描栅显微成像理论

Theory of scanning gate microscopy imaging of the supercurrent distribution in a planar Josephson junction

K. Kaperek, S. Heun, M. Carrega, P. Wójcik, M. P. Nowak

摘要:

本文利用扫描门显微镜技术,从理论上研究了在垂直磁场作用下超导-正常-超导平面结中超导电流分布的映射。我们发现,如果结中的通量设置为接近夫琅和费图案的最大值,则约瑟夫森涡旋中排列的反向传播超电流的分布可以通过扫描探针尖端感应的临界电流的变化来映射。相反,当磁场将结驱动到夫琅和费模式中的超电流最小值时,超导相适应,并且尖端总是增加超电流。垂直的磁场导致约瑟夫森涡旋的形成,其高度透明的结的延伸取决于电流的流通方向。我们表明,这导致一个不对称的超电流分布在交界处,这可以通过扫描栅显微镜揭示。我们解释我们的研究结果的基础上的数值计算的短和长结的限制,并提供了一个现象学模型所观察到的现象。

英文摘要:

We theoretically investigate the mapping of the supercurrent distribution in a planar superconductor-normal-superconductor junction in the presence of a perpendicular magnetic field via the scanning gate microscopy technique. We find that the distribution of counter-propagating supercurrents aligned in Josephson vortices can be mapped by the change of the critical current induced by the tip of the scanning probe, if the flux in the junction is set close to maxima of the Fraunhofer pattern. Instead, when the magnetic field drives the junction to a supercurrent minimum in the Fraunhofer pattern, the superconducting phase adapts, and the tip always increases the supercurrent. The perpendicular magnetic field leads to the formation of Josephson vortices, whose extension for highly transparent junctions depends on the current circulation direction. We show that this leads to an asymmetric supercurrent distribution in the junction and that this can be revealed by scanning gate microscopy. We explain our findings on the basis of numerical calculations for both short- and long-junction limits and provide a phenomenological model for the observed phenomena.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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