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arXiv 0707.4413cond-mat.supr-con
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面内磁场不重合时薄膜超导体/绝缘体/超导体结中的约瑟夫森效应

Josephson effect in thin-film superconductor/insulator/superconductor junctions with misaligned in-plane magnetic fields

J. Linder, A. Sudbø

摘要:

我们研究了由两个薄膜s波超导体组成的隧道结,在存在错位的面内交换场的情况下,两个超导体被一个薄的绝缘势垒隔开。我们发现了一个有趣的超导相位差和交换场的相对取向之间的相互作用,表现在约瑟夫森电流通过结。具体地,这可以写作$I_\text{J}^\text{C} = (I_0+I_m ~ \cosϕ) \sinΔθ$,其中I_0和I_m是常数,$ϕ$是交换场的相对取向,而$Δθ$是超导相位差。类似的结果最近已经在其他S/I/S结共存helmagnetic或铁磁秩序。我们自洽地计算了超导序参量,并定量地研究了失调交换场对约瑟夫森电流的影响,以观察I_m是否对约瑟夫森电流有明显的影响。发现在足够低的温度和接近临界值的磁场下,I_0和Im的大小变得相当,这与以前的工作一致。从我们的分析结果,它随后在本系统中的约瑟夫森电流可以控制在一个明确定义的方式通过旋转的交换场两侧的结。我们讨论了这个命题的一个可能的实验实现。

英文摘要:

We study a tunnel junction consisting of two thin-film s-wave superconductors separated by a thin, insulating barrier in the presence of misaligned in-plane exchange fields. We find an interesting interplay between the superconducting phase difference and the relative orientation of the exchange fields, manifested in the Josephson current across the junction. Specifically, this may be written $I_\text{J}^\text{C} = (I_0+I_m ~ \cosϕ) \sinΔθ$, where I_0 and I_m are constants, and $ϕ$ is the relative orientation of the exchange fields while $Δθ$ is the superconducting phase difference. Similar results have recently been obtained in other S/I/S junctions coexisting with helimagnetic or ferromagnetic order. We calculate the superconducting order parameter self-consistently, and investigate quantitatively the effect which the misaligned exchange fields constitute on the Josephson current, to see if I_m may have an appreciable effect on the Josephson current. It is found that I_0 and I_m become comparable in magnitude at sufficiently low temperatures and fields close to the critical value, in agreement with previous work. From our analytical results, it then follows that the Josephson current in the present system may be controlled in a well-defined manner by a rotation of the exchange fields on both sides of the junction. We discuss a possible experimental realization of this proposition.

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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