3D nature of ZrTe${}_5$ band structure measured by high-momentum-resolution photoemission spectroscopy

Abstract

We have performed a systematic high-momentum-resolution photoemission study on ZrTe${}_5$ using $6$ eV photon energy. We have measured the band structure near the $\hat{I}“$ point, and quantified the gap between the conduction and valence band as $18\le \hat{I}”\le 29$ meV. We have also observed photon-energy-dependent behavior attributed to final-state effects and the 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 ZrTe${}_5$ is not a 3D strong topological insulator nor a 3D Dirac semimetal. Therefore, our experiment is consistent with ZrTe${}_5$ being a 3D weak topological insulator.

8 pages, 5 figures