Searching for a promising topological Dirac nodal-line semimetal by angle resolved photoemission spectroscopy

Topological semimetals, in which conduction and valence bands cross each other at either discrete points or along a closed loop with symmetry protected in the momentum space, exhibited great potential in applications of optical devices as well as heterogeneous catalysts or antiferromagnetic spintronics, especially when the crossing points/lines matches Fermi level (E (F)). It is intriguing to find the 'ideal' topological semimetal material, in which has a band structure with Dirac band-crossing located at E (F) without intersected by other extraneous bands. Here, by using angle resolved photoemission spectroscopy, we investigate the band structure of the so-called 'square-net' topological material ZrGeS. The Brillouin zone (BZ) mapping shows the Fermi surface of ZrGeS is composed by a diamond-shaped nodal line loop at the center of BZ and small electron-like Fermi pockets around X point. The Dirac nodal line band-crossing located right at E (F), and shows clearly the linear Dirac band dispersions within a large energy range >1.5 eV below E (F), without intersected with other bands. The obtained Fermi velocities and effective masses along Gamma-X, Gamma-M and M-X high symmetry directions were 4.5-5.9 eV angstrom and 0-0.50 m (e), revealing an anisotropic electronic property. Our results suggest that ZrGeS, as a promising topological nodal line semimetal, could provide a promising platform to investigate the Dirac-fermions related physics and the applications of topological devising.

Automated summary

The study investigates the band structure of the "square-net" topological material ZrGeS, revealing its unique electronic properties suitable for exploring Dirac-fermions related physics and applications of topological devising.