论文标题
单层x3yz6家族中的拓扑半学相（x = nb，ta，y = si，ge，sn，z = s，se，te），具有丰富的节点和节点
Topological semimetal phases in a family of monolayer X3YZ6 (X=Nb,Ta, Y=Si,Ge,Sn, Z=S,Se,Te) with abundant nodal lines and nodes
论文作者
论文摘要
单层X3YZ6（x = nb，ta，y = si，ge，sn，z = s，se，te）的电子和拓扑特性已借助第一原理计算。这种材料属于具有丰富淋巴结线和节点的拓扑半学（TMS）。考虑到它们相似的特性，我们专注于TA3SNTE6和TA3SISE的分析。旋转轨道耦合（SOC）的当下导致从I型节点线到狄拉克点以及II型dirac点的消失。三维（3D）带图生动地再现了节点和淋巴结线的特征。 （110）边缘状态中平坦带的出现进一步证实了它们的非平凡拓扑特性。我们还探索了不同节点线（节点），晶体对称性和SOC之间的关系。 I型淋巴结线受MZ的保护，而在没有SOC的情况下我的对称性。即使在SOC存在的情况下，对称破裂也会导致频段分裂。单层X3YZ6可用作二维（2D）TMS的候选物，并为进一步研究有趣的物理现象提供了一个平台。
The electronic and topological properties of single-layer X3YZ6 (X=Nb,Ta, Y=Si,Ge,Sn, Z=S,Se,Te) materials have been studied with the aid of first principles calculations. This kind of materials belong to topological semimetals (TMs) with abundant nodal lines and nodes. Considering their similar properties, we focus on the analysis of Ta3SnTe6 and Ta3SiSe6. The present of spin-orbit coupling (SOC) leads to the transition from type-I nodal lines to Dirac points as well as the disappear of type-II Dirac points. The three-dimensional (3D) band diagrams reproduce vividly the characteristics of nodes and nodal lines. The appearance of the flat bands in (110) edge states further confirm their nontrivial topological properties. We also explore the relationship among different nodal lines (nodes), crystal symmetry and SOC. The type-I nodal lines are protected by Mz and My symmetry in the absent of SOC. Symmetry breaking leads to band splitting even in the presence of SOC. The single-layer X3YZ6 can be used as candidates for two-dimensional (2D) TMs and provide a platform for further study of interesting physical phenomena.
