Nonsymmorphic symmetry protected nodal lines in layered topological semimetal Ta3GeTe6

Abstract

Topological semimetals have garnered significant attention due to their distinctive physical properties. However, the ideal material platforms for studying these phenomena remain limited. Here, we report the synthesis and nontrivial topological properties of high-quality van der Waals material Ta3GeTe6. Angle-resolved photoemission spectroscopy studies performed systematically on the as-grown Ta3GeTe6 single crystal along different high-symmetry directions reveal the formation of two nodal lines located near 0.07 and 0.55 eV below EF along the loop X-U-R-S, which arises from band crossings protected by nonsymmorphic symmetry. Furthermore, the nodal lines near the Fermi level along the S-R and S-X directions exhibit a flat feature. The discovery of this material enriches the family of topological nodal line semimetals and provides a promising platform for future investigations into exotic electronic correlation phenomena and potential device applications.