Electronic structure of rare earth based ternary nodal line semimetal

Lanthanide-based LnSbTe materials offer an opportunity to explore the interplay of magnetism and topological properties, driven by nonsymmorphic crystalline symmetry, interactions with rare-earth 4f orbitals, and strong spin-orbit coupling (SOC). In this study, we investigate the electronic structure of a member of the LnSbTe family that crystallizes in the ZrSiS-type nonsymmorphic tetragonal structure. Through comprehensive low-temperature bulk measurements, we identify antiferromagnetic ordering below 7.45 K, with an additional phase transition at 7.15 K. Through the usage of angle-resolved photoemission spectroscopy measurements, we reveal a roughly diamond-shaped Fermi pocket within the k_z=0 plane, however with a reduced spectral intensity along the Γ-M direction resulting from strong spin orbit interactions. These findings, supported by density-functional theory calculations, emphasizes its potential as a platform for investigating the intricate interplay between topology, magnetism, and SOC in quantum materials.