Vortices in a mesoscopic cone: A superconducting tip in the presence of an applied field
Vortices in a mesoscopic cone: A superconducting tip in the presence of an applied field
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DOI：
10.1103/physrevb.77.054511
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发表时间：
2008-02-01
影响因子：
3.7
通讯作者：
Peeters, F. M.
中科院分区：
文献类型：
--
作者：
Chen, Yajiang;Doria, Mauro M.;Peeters, F. M.
从理论上研究了圆锥形状的介观超导体及其相干长度量级的大小。垂直于其圆形基础施加外部磁场，并在金兹堡-朗道理论的框架内获得涡旋态。我们发现了由巨型涡旋态（GVS）、弯曲多涡旋态（MVS）以及两者的组合组成的图案。结果总结在相图中，其中 GVS 和 MVS 状态根据应用的场和几何参数确定。我们发现，在顶角非常小的情况下，超导性持续到比上临界场 (H-c2) 大得多的场。这些结果有助于了解超导尖端的特性，超导尖端目前用于扫描隧道显微镜，在存在外部施加场的情况下。
A mesoscopic superconductor in the shape of a circular cone, and size of the order of the coherence length, is investigated theoretically. The external magnetic field is applied perpendicular to its circular basis, and vortex states are obtained in the framework of the Ginzburg-Landau theory. We find patterns made of giant vortex states (GVS), curved multivortex states (MVS), and a combination of both of them. The results are summarized in phase diagrams, where the GVS and MVS regimes are determined according to the applied field and geometric parameters. We find that superconductivity persists up to fields much larger than the upper critical field (H-c2) in case of a very small apex angle. The results are relevant to understand the properties of superconducting tips, which are currently used in scanning tunneling microscopy, in the presence of an external applied field.