Electronic structure of a nodal line semimetal candidate TbSbTe

The LnSbTe (Ln = Lanthanides) family, like isostructural ZrSiS-type compounds, has emerged as a fertile playground for exploring the interaction of electronic correlations and magnetic ordering with the nodal line electronic structure band topology. Here, we report a detailed electronic band structure of TbSbTe, corroborated by electrical transport, thermodynamic, and magnetic studies. Temperature-dependent magnetic susceptibility and thermodynamic transport studies indicate the onset of antiferromagnetic ordering below TN ∼ 5.1 K. The electronic band structure, carried out with high-resolution angle-resolved photoemission spectroscopy (ARPES) measurements aided with density functional theory based first-principles calculations, reveal presence of a nonsymmorphic symmetry protected Dirac crossing in the Γ − X high symmetry direction, which is part of a nodal line along the X − R high symmetry direction. Another Dirac crossing occurs along the Γ −X direction at a relatively higher binding energy, which occurs from C_2v symmetry which is gapped in the theoretical calculations with the effect of spin orbit coupling considered. This study opens an avenue to further uncover the intricate interplay among symmetry-protected topological band structure, spin-orbit coupling, and magnetism in this material and LnSbTe family, in general.