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arXiv 0801.1145cond-mat.supr-con
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超导异质结中Josephson电流的自旋轨道耦合效应

Spin-orbital coupling effect on Josephson current through a superconductor heterojunction

Z. H. Yang, Y. H. Yang, J. Wang, K. S. Chan

摘要:

研究了超导异质结中自旋轨道耦合效应对约瑟夫森电流的影响。超导异质结由两个s波超导体和它们之间的二维电子气层组成。在2DEG区域考虑了Rashba型(RSOC)和/或Dresselhaus型(DSOC)的自旋轨道耦合。利用晶格Bogoliubov-de Gennes方程和Keldysh公式计算了流过SC/2DEG/SC结的直流超导电流,发现临界电流$I_c$随SOC强度和2DEG层长的变化呈现阻尼振荡,特别是RSOC和DSOC的强度比也会引起SC/2DEG/SC结的$0$态和$π$态之间的转换.这种$0$ - $π$转变是由于二维系统中的SOC可以导致对流动电子的伪磁效应,如铁磁体的效应,因为系统的时间反演对称性已经被具有不同宏观相的两个SC引线打破。

英文摘要:

We study spin-orbital coupling effect on the Josephson current through a superconductor (SC) heterojunction, consisting of two s-wave superconductors and a two-dimensional electron gas (2DEG) layer between them. The Rashba-type (RSOC) and/or Dresselhaus-type (DSOC) of spin-orbital coupling are considered in the 2DEG region. By using the lattice Bogoliubov-de Gennes equation and the Keldysh formalism, we calculate the DC supercurrent flowing through the junction and find that the critical current $I_c$ exhibits a damped oscillation with both the strength of SOC and the layer length of 2DEG; especially, the strength ratio between RSOC and DSOC can also induce switching between the $0$ state and the $π$ state of the SC/2DEG/SC junction as well. This $0$-$π$ transition results from the fact that SOC in a two-dimension system can lead to a pseudo-magnetic effect on the flowing electrons like the effect of a ferromagnet, since the time reversal symmetry of the system has already been broken by two SC leads with different macroscopic phases.

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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