Angle-resolved photoemission spectroscopy(ARPES) , DFT calculations and theoretical description of a weak topological insulator RhBi2

We used ultrahigh resolution ARPES, DFT calculations and theoretical model to study the surface state of the weak topological insulator RhBi2. We observed two surface Dirac points from our ARPES data and it has a good agreement with DFT calculations. In addition, we found that there is a saddle point, which is related to a van Hove singularity (VHS), around the Dirac point around the zone boundary. The VHS is expected to enhance the impact of electronic correlations and cause quantum many body instabilities such as superconductivity, ferromagnetism etc.

我们采用超高分辨率角分辨光电子能谱（ARPES）、密度泛函理论（DFT）计算及理论模型，对弱拓扑绝缘体RhBi2的表面态展开研究。通过ARPES数据，我们观测到两个表面狄拉克点，且这一结果与DFT计算高度吻合。此外，我们发现在布里渊区边界附近的狄拉克点周围存在一个鞍点，该鞍点与范霍夫奇点（VHS）相关。范霍夫奇点（VHS）有望增强电子关联的效应，并引发超导、铁磁等量子多体不稳定性。