Bound States of a Ferromagnetic Wire in a Superconductor.
Bound States of a Ferromagnetic Wire in a Superconductor.
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DOI：
10.1103/physrevlett.115.127003
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发表时间：
2015-01
影响因子：
8.6
通讯作者：
J. Sau;P. Brydon
中科院分区：
文献类型：
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作者：
J. Sau;P. Brydon
我们考虑了超导体中强各向异性铁磁杂质的束缚态问题，受到最近声称在超导基底上的铁磁线末端观察到马约拉纳模式的实验的启发[S. Nadj-Perge 等人，Science 346, 602 (2014)]。概括球对称杂质束缚态的成功理论，我们使用解析和数值方法考虑线状势。我们发现，远离导线末端的束缚态形成具有明显范霍夫奇点的能带，从而在局部态密度中产生子能隙峰值。为了使导线足够强的磁化，我们表明该过程通常会在导线末端附近的局部态密度中产生零能量处的尖峰。这个零能量峰与上述实验中观察到的马约拉纳模式的特征具有定性的相似性。
We consider the problem of bound states in strongly anisotropic ferromagnetic impurities in a superconductor, motivated by recent experiments that claim to observe Majorana modes at the ends of ferromagnetic wires on a superconducting substrate [S. Nadj-Perge et al., Science 346, 602 (2014)]. Generalizing the successful theory of bound states of spherically symmetric impurities, we consider a wirelike potential using both analytical and numerical approaches. We find that away from the ends of the wire the bound states form bands with pronounced van Hove singularities, giving rise to subgap peaks in the local density of states. For sufficiently strong magnetization of the wire, we show that this process generically produces a sharp peak at zero energy in the local density of states near the ends of the wire. This zero-energy peak has qualitative similarities to the claimed signature of a Majorana mode observed in the aforementioned experiment.