论文标题
拓扑半学的平行和反平行的螺旋表面状态
Parallel and anti-parallel helical surface states for topological semimetals
论文作者
论文摘要
携带Z型单极电荷C的Weyl点具有与螺旋表面状态（HSSS）相关的散装对应（BSC）。当| c | > 1，多HSS可以并行出现。但是，当一对携带C = \ pm 1的Weyl点相遇时，可以获得一个携带C = 0的Dirac点，并且BSC消失。尽管如此，作为参考文献的最新研究。 [ARXIV：2201.03238]表明，当系统具有时间反转（T） - glide（g）对称（θ= tg）时，新的BSC可以生存，即与新的Z2-type Monopole电荷Q相关。在本文中，我们系统地回顾并讨论了Weyl和Dirac点的并行和平行的多HSS，并带有两种不同类型的单子电荷。提供了两个材料示例，以了解多HSS的整个配置。一个携带Z型单极电荷C，显示了三种Weyl点的局部和全球拓扑，这导致了平行的多HSSS。另一个携带Z2型单极电荷Q，仅显示θ不变迪拉克点的全局拓扑，并伴有反平行的多HSSS。这些多样化的拓扑表面状态不仅为散装堕落提供了本地和全球拓扑，而且还为各种拓扑阶段提供了平台。
Weyl points, carrying a Z-type monopole charge C, have bulk-surface correspondence (BSC) associated with helical surface states (HSSs). When |C| > 1, multi-HSSs can appear in a parallel manner. However, when a pair of Weyl points carrying C = \pm 1 meet, a Dirac point carrying C = 0 can be obtained and the BSC vanishes. Nonetheless, a recent study in Ref. [arXiv:2201.03238] shows that a new BSC can survive for Dirac points when the system has time-reversal (T )-glide (G) symmetry (Θ=TG), i.e., anti-parallel double/quad-HSSs associated with a new Z2-type monopole charge Q appears. In this paper, we systematically review and discuss both the parallel and anti-parallel multi-HSSs for Weyl and Dirac points, carrying two different kinds of monopole charges. Two material examples are offered to understand the whole configuration of multi-HSSs. One carries the Z-type monopole charge C, shows both local and global topology for three kinds of Weyl points, and it leads to parallel multi-HSSs. The other carries the Z2-type monopole charge Q, only showing the global topology for Θ-invariant Dirac points, and it is accompanied by antiparallel multi-HSSs. These diverse topological surface states not only offer the local and global topology for the bulk degeneracy but also offer platforms to various topological phases.
