论文标题
在三斜rhbi2中发现弱拓扑绝缘状态和范霍夫的奇异性
Discovery of a weak topological insulating state and van Hove singularity in triclinic RhBi2
论文作者
论文摘要
时间逆转对称（TRS）不变拓扑绝缘子（TIS）在拓扑材料的领域中占据范式的作用，直到其发育的起源。除了受TR的保护“强” tis之外，还在早期意识到，存在更混淆的弱拓扑绝缘子（WTI）。 WTI依赖于翻译对称性和仅在某些方向上展示拓扑表面状态，这使得与强TI的实验成功相匹配变得更加困难。我们在这里报告属于最佳空间群P1的RHBI2中的WTI状态的发现，这是唯一一个对称性表明特征值列举了所有可能的不变物，这是由于缺乏其他约束结晶对称性所致。我们的ARPE，DFT计算和有效模型揭示了位于Dirac点附近的座椅表面状态，导致沿着（100）方向靠近费米能量的（100）方向产生van Hove奇异性（VHS）。由于外来特征的结合，该材料作为新型量子效应的材料平台提供了巨大的潜力。
Time reversal symmetric (TRS) invariant topological insulators (TIs) fullfil a paradigmatic role in the field of topological materials, standing at the origin of its development. Apart from TRS protected 'strong' TIs, it was realized early on that more confounding weak topological insulators (WTI) exist. WTIs depend on translational symmetry and exhibit topological surface states only in certain directions making it significantly more difficult to match the experimental success of strong TIs. We here report on the discovery of a WTI state in RhBi2 that belongs to the optimal space group P1, which is the only space group where symmetry indicated eigenvalues enumerate all possible invariants due to absence of additional constraining crystalline symmetries. Our ARPES, DFT calculations, and effective model reveal topological surface states with saddle points that are located in the vicinity of a Dirac point resulting in a van Hove singularity (VHS) along the (100) direction close to the Fermi energy. Due to the combination of exotic features, this material offers great potential as a material platform for novel quantum effects.
