物理学进展

物理学进展 ›› 2023, Vol. 43 ›› Issue (5): 131-141.doi: 10.13725/j.cnki.pip.2023.05.001

所属专题： 2023年, 第43卷

• •    下一篇

向列型三态超导体中的磁通涡旋态

  

  1. 1. 南京大学物理学院，固体微结构物理国家重点实验室，南京 210093 2. 人工微结构科学与技术协同创新中心，南京大学，南京 210093
  • 出版日期:2023-10-20 发布日期:2023-10-23

Vortex state in a nematic triplet superconductor

  1. 1. National Laboratory of Solid State Microstructures & School of Physics, Nanjing University, Nanjing, 210093, China 2. Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
  • Online:2023-10-20 Published:2023-10-23
  • Supported by:

    National Key R&D Program of China (Grant No. 2022YFA1403201) and National Natural Science Foundation of China (Grant No. 12274205 and No. 11874205)

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摘要：

在掺杂拓扑绝缘体 CuxBi2Se3 中，向列型三态超导电性的发现引发了人们对指认三态超导 中 d-矢量的兴趣，它与能隙函数的反节点方向有关，并且决定了该超导体是否为拓扑。我们对向 列型自旋三态 px 波超导体的涡旋态性质进行了自洽分析。我们首先推导了 Ginzburg-Landau 理 论来确定涡旋和涡旋晶格的形状。我们发现孤立涡旋的空间轮廓沿着反节点方向拉长，涡旋晶格 是一个沿 x 方向拉长的形变了的三角晶格，在圆形费米面的特定情况下会变成正方形。最后，我 们使用微观的 Bogoliubov-de Gennes 方程自洽计算了孤立涡旋和涡旋晶格的局域态密度。我们发 现在隙间低能量下，局域态密度的轮廓始终沿着反节点方向拉长。我们的发现对于实验上探测向 列型三态超导体中能隙函数的反节点方向以及进而确定超导态的拓扑性质（如在 CuxBi2Se3 中） 具有重要价值。

关键词: px 波超导体, Ginzburg-Landau 理论, Bogoliubov-de Gennes 方程, 磁通涡旋, 磁通 涡旋晶格 

Abstract:

The discovery of nematic triplet superconductivity in doped topological insulators CuxBi2Se3 triggers interest in the identification of the d-vector of the triplet, which is related to the antinodal direction of the gap function and determines whether the superconductor is topological. We perform self-consistent analysis of the vortex state properties in a nematic spin-triplet px-wave superconductor. We first derive a Ginzburg-Landau theory to determine the shape of the vortex and vortex lattice. We find the spatial profile of the isolated vortex is elongated along the antinodal direction, and the vortex lattice is a distorted triangular lattice elongated along x, becoming square in the specific case of a small circular Fermi surface. Finally, we calculate the local density of states self-consistently for an isolated vortex and the vortex lattice using the microscopic Bogoliubov-de Gennes equation. We find that the profile of the local density of states at low in-gap energies is always elongated along the antinodal direction. Our findings are valuable for the experimental detection of the antinodal direction of the gap function in nematic triplet superconductors, and subsequently the identification of the topological character of the superconducting state as in CuxBi2Se3.

Key words: px-wave superconductivity, Ginzburg-Landau theory, Bogoliubov-de Gennes equation, vortex, vortex lattice 

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