Abstract
We have performed a systematic high-momentum-resolution photoemission study on using 6-eV photon energy. We have measured the band structure near the point, and quantified the gap between the conduction and valence band as meV. We have also observed photon-energy-dependent behavior attributed to final-state effects and the three-dimensional (3D) nature of the material's band structure. Our interpretation indicates the gap is intrinsic and reconciles discrepancies on the existence of a topological surface state reported by different studies. The existence of a gap suggests that is not a 3D strong topological insulator nor a 3D Dirac semimetal. Therefore, our experiment is consistent with being a 3D weak topological insulator.
- Received 21 January 2017
DOI:https://doi.org/10.1103/PhysRevB.95.195119
©2017 American Physical Society