Creation of equal-spin triplet superconductivity at the Al/EuS interface
Creation of equal-spin triplet superconductivity at the Al/EuS interface
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DOI：
10.1038/s41467-018-07597-w
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发表时间：
2018-12-07
影响因子：
16.6
通讯作者：
Scheer, E.
中科院分区：
文献类型：
--
作者：
Diesch, S.;Machon, P.;Scheer, E.
在传统的超导体中，自旋相反的电子被束缚成库珀对。然而，当超导体与非均匀有序的铁磁体接触时，在界面处会出现一种奇异的超导性，电子被束缚成三种可能的自旋三重态。具有相同自旋的三重态对在低耗散自旋电子学中起着至关重要的作用。尽管通过铁磁体观察到了超电流，但仍然缺少等自旋三重态对存在的光谱证据。在这里，我们展示了一个理论模型，揭示了一个特征的间隙结构的准粒子态密度提供了一个独特的签名的存在下，等自旋三重态对。通过扫描隧道谱，我们测量了局域态密度，揭示了三重态对的自旋组态。我们证明了Al/EuS界面凭借其自旋相关的传输引起强烈的和可调的自旋混合。
In conventional superconductors, electrons of opposite spins are bound into Cooper pairs. However, when the superconductor is in contact with a non-uniformly ordered ferromagnet, an exotic type of superconductivity can appear at the interface, with electrons bound into three possible spin-triplet states. Triplet pairs with equal spin play a vital role in low-dissipation spintronics. Despite the observation of supercurrents through ferromagnets, spectroscopic evidence for the existence of equal-spin triplet pairs is still missing. Here we show a theoretical model that reveals a characteristic gap structure in the quasiparticle density of states which provides a unique signature for the presence of equal-spin triplet pairs. By scanning tunnelling spectroscopy we measure the local density of states to reveal the spin configuration of triplet pairs. We demonstrate that the Al/EuS interface causes strong and tunable spin-mixing by virtue of its spin-dependent transmission.