Refined symmetry indicators for topological superconductors in all space groups
Refined symmetry indicators for topological superconductors in all space groups
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DOI：
10.1126/sciadv.aaz8367
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发表时间：
2019-09
期刊：
影响因子：
13.6
通讯作者：
Seishiro Ono;H. Po;Haruki Watanabe
中科院分区：
文献类型：
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作者：
Seishiro Ono;H. Po;Haruki Watanabe
利用超导体的对称性，建立了一个通用的框架来帮助诊断超导体中的非平凡拓扑。拓扑超导体是物质的奇异相，具有强大的表面态，可以用于拓扑量子计算。寻找拓扑超导体的一个有用的指导原则是将拓扑不变量与正态费米表面上的配对顺序参数的行为联系起来。然而，现有的公式对于最近提出的拓扑晶体超导体的预测是不够的。在这项工作中，我们提出了拓扑（晶体）超导体的对称指标理论，以涵盖所有空间群。我们的主要结果是在各种对称设置下超导体的指示群的详尽计算。我们通过分析具有或不具有反转对称性的四重对称超导体进一步说明了这种方法的力量，并表明这些指标可以诊断具有不同维数表面状态的拓扑超导体或指示体激发谱中的无间隙。
A general framework is developed to aid the diagnosis of nontrivial topology in superconductors using their symmetry properties. Topological superconductors are exotic phases of matter featuring robust surface states that could be leveraged for topological quantum computation. A useful guiding principle for the search of topological superconductors is to relate the topological invariants with the behavior of the pairing order parameter on the normal-state Fermi surfaces. The existing formulas, however, become inadequate for the prediction of the recently proposed classes of topological crystalline superconductors. In this work, we advance the theory of symmetry indicators for topological (crystalline) superconductors to cover all space groups. Our main result is the exhaustive computation of the indicator groups for superconductors under a variety of symmetry settings. We further illustrate the power of this approach by analyzing fourfold symmetric superconductors with or without inversion symmetry and show that the indicators can diagnose topological superconductors with surface states of different dimensionalities or dictate gaplessness in the bulk excitation spectrum.