Fractional ac Josephson effect in p- and d-wave superconductors
Fractional ac Josephson effect in p- and d-wave superconductors
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DOI：
10.1140/epjb/e2004-00066-4
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发表时间：
2004-02-01
影响因子：
1.6
通讯作者：
Yakovenko, VM
中科院分区：
文献类型：
--
作者：
Kwon, HJ;Sengupta, K;Yakovenko, VM
对于两个p（x）波或两个d波超导体之间的约瑟夫森结的某些取向，亚能隙Andreev束缚态在约瑟夫森电流I和相位差φ：I之间产生与sin（φ/2）成比例的4 π周期关系。因此，交流约瑟夫森电流在bar上具有分数频率eV/（h），其中V是直流电压。在隧穿极限中，约瑟夫森电流正比于电子隧穿振幅的一次方（不是平方）。因此，非传统超导体之间的约瑟夫森电流是由单个电子携带的，而不是由库珀对携带的。通过测量结的微波辐射频谱，可以在实验上观察到分数交流约瑟夫森效应。我们还研究了单重态s波和三重态p（x）波之间的结，以及手征p（x）+/- ip（y）波超导体之间的结。
For certain orientations of Josephson junctions between two p(x)-wave or two d-wave superconductors, the subgap Andreev bound states produce a 4pi-periodic relation between the Josephson current I and the phase difference phi: I proportional to sin(phi/2). Consequently, the ac Josephson current has the fractional frequency eV/(h) over bar, where V is the dc voltage. In the tunneling limit, the Josephson current is proportional to the first power (not square) of the electron tunneling amplitude. Thus, the Josephson current between unconventional superconductors is carried by single electrons, rather than by Cooper pairs. The fractional ac Josephson effect can be observed experimentally by measuring frequency spectrum of microwave radiation from the junction. We also study junctions between singlet s-wave and triplet p(x)-wave, as well as between chiral p(x) +/- ip(y)-wave superconductors.