arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1908.08360cond-mat.supr-con
收藏

约瑟夫森结中的无序和临界电流变化

Disorder and Critical Current Variability in Josephson Junctions

Miguel Antonio Sulangi, T. A. Weingartner, N. Pokhrel, E. Patrick, M. Law, P. J. Hirschfeld

摘要:

本文从理论上研究了Nb/Al-AlO $_x$ /Nb约瑟夫森结的临界电流随不同类型的无序变化的原因。我们考虑以下无序源:Al层内的空位; AlO $_x$层中的厚度变化;以及“针孔”(即,点接触)。所有的计算都是通过求解微观Bogoliubov-de Gennes哈密顿量自洽进行的。据发现,一个小浓度的空位内的Al层是足以抑制的临界电流,而少量的厚区域的氧化物层的存在诱导类似的效果。针孔的情况下,发现导致异常的行为,既不类似于一个纯隧道结,也不是SNS结,但这两个限制之间插入的制度。我们评论的程度,这三个场景中的每一个描述的实际情况,目前在这些路口。

英文摘要:

We investigate theoretically the origins of observed variations in the critical currents of Nb/Al-AlO$_x$/Nb Josephson junctions in terms of various types of disorder. We consider the following disorder sources: vacancies within the Al layer; thickness variations in the AlO$_x$ layer; and "pinholes" (i.e., point contacts) within the AlO$_x$ layer. The calculations are all performed by solving the microscopic Bogoliubov-de Gennes Hamiltonian self-consistently. It is found that a small concentration of vacancies within the Al layer is sufficient to suppress the critical current, while the presence of a small number of thick regions of the oxide layer induces a similar effect as well. The pinhole scenario is found to result in anomalous behavior that resembles neither that of a pure tunnel junction nor that of an SNS junction, but a regime that interpolates between these two limits. We comment on the degree to which each of the three scenarios describes the actual situation present in these junctions.

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。

↑