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.