Electronic structure of pyrochlore lattice material CsBi₂ studied by high-resolution ARPES

Pyrochlore lattice, consisting of corner-sharing tetrahedra, is known to host diverse quantum phenomena originating from its geometric symmetry. Although novel electronic states such as Dirac cones have been proposed as a possible origin of such phenomena, their experimental realizations remain scarce. In this study, we focused on the pyrochlore-lattice superconductor CsBi₂. To gain insight into its unusual electronic structure and the mechanism of superconductivity, we performed high-resolution ARPES measurements on the (111) surface of CsBi₂. We successfully observed the Dirac band dispersion protected by screw rotation symmetry. In this talk, we will also present observations of flat bands and saddle points, and discuss the relationship between the electronic states and superconductivity.