Creation of Spin-Triplet Cooper Pairs in the Absence of Magnetic Ordering.
Creation of Spin-Triplet Cooper Pairs in the Absence of Magnetic Ordering.
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DOI：
10.1103/physrevlett.120.037701
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发表时间：
2017-10
影响因子：
8.6
通讯作者：
Daniel Breunig;P. Burset;B. Trauzettel
中科院分区：
文献类型：
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作者：
Daniel Breunig;P. Burset;B. Trauzettel
在超导自旋电子学中，按需产生自旋三重态库珀对是必不可少的。到目前为止，这样做的建议集中在混合结构中，超导体（SC）与磁有序材料（或外部磁场）相结合。相反，我们确定了一种新的方法来创建和隔离自旋三重态库珀对在没有任何磁性排序。这一成就是唯一可能的，因为我们驱动一个系统与强大的自旋轨道相互作用的狄拉克表面状态的强拓扑绝缘体（TI）的平衡。特别是，我们认为一个双极TI-SC-TI结，其中在外部引线的电化学电位在其整体符号不同。其结果是，我们发现，非局部的单重态配对跨结是完全抑制任何激发能量。因此，这个结作为一个完美的自旋三重态过滤器横跨SC，通过交叉Andreev反射产生等自旋库珀对。
In superconducting spintronics, it is essential to generate spin-triplet Cooper pairs on demand. Up to now, proposals to do so concentrate on hybrid structures in which a superconductor (SC) is combined with a magnetically ordered material (or an external magnetic field). We, instead, identify a novel way to create and isolate spin-triplet Cooper pairs in the absence of any magnetic ordering. This achievement is only possible because we drive a system with strong spin-orbit interaction-the Dirac surface states of a strong topological insulator (TI)-out of equilibrium. In particular, we consider a bipolar TI-SC-TI junction, where the electrochemical potentials in the outer leads differ in their overall sign. As a result, we find that nonlocal singlet pairing across the junction is completely suppressed for any excitation energy. Hence, this junction acts as a perfect spin-triplet filter across the SC, generating equal-spin Cooper pairs via crossed Andreev reflection.