论文标题
在中心对称超导体中连接双电荷淋巴结的结构
Linking structures of doubly charged nodal surfaces in centrosymmetric superconductors
论文作者
论文摘要
在拓扑半学和淋巴结超导体中，占用和未占用的带之间的带横梁形成稳定的节点点/线/表面，并带有量化的拓扑电荷。特别是，在中心对称系统中，费米能$ e_f $处的一些节点结构带有两个不同的拓扑电荷，因此被称为双电荷节点。在这里，我们表明，三维中的中心对称超导体的双重充电淋巴结始终会形成奇特的链接结构，这些结构具有淋巴结点或在$ e_f $以下的占用频段之间形成的线或线。这样的链接结构自然可以解释$ e_f $以下节点的电荷与$ e_f $以$ e_f $的两个电荷之间的固有关系。基于Altland-Zirnbauer（AZ）-Type十倍的节点分类，并具有额外的反转$ \ Mathcal {I} $对称性，该节点称为AZ $+\ Mathcal {I} $分类，我们提供了双重充电Nodes indermemmpersmmpersmpersmmets mectemmmets systems的链接结构的完整列表。双电荷节点的连接结构清楚地表明，不仅在节点周围的本地频带结构，而且全球频段结构在表征无间隙拓扑阶段中起着至关重要的作用。
In topological semimetals and nodal superconductors, band crossings between occupied and unoccupied bands form stable nodal points/lines/surfaces carrying quantized topological charges. In particular, in centrosymmetric systems, some nodal structures at the Fermi energy $E_F$ carry two distinct topological charges, and thus they are called doubly charged nodes. Here we show that doubly charged nodal surfaces of centrosymmetric superconductors in three-dimensions always develop peculiar linking structures with nodal points or lines formed between occupied bands below $E_F$. Such linking structures can naturally explain the inherent relationship between the charge of the node below $E_F$ and the two charges of the nodal surfaces at $E_F$. Based on the Altland-Zirnbauer (AZ)-type ten-fold classification of nodes with additional inversion $\mathcal{I}$ symmetry, which is called the AZ$+\mathcal{I}$ classification, we provide the complete list of linking structures of doubly charged nodes in centrosymmetric systems. The linking structures of doubly charged nodes clearly demonstrate that not only the local band structure around the node but also the global band structure play a critical role in characterizing gapless topological phases.
