Observation of gapless nodal-line states in NdSbTe

The recent research interest in ZrSiS-type lanthanide (Ln)-based LnSbTe family of materials comes from the possibility of intermixing of electronic correlations and magnetic ordering of the Ln 4f electrons with topological states including nodal-line and non-symmorphic Dirac states that the ZrSiS family is famous for. In this work, we carried out a study on one such material – NdSbTe – by using angle-resolved photoemission spectroscopy supported by first-principles calculations and thermodynamic measurements. We present experimental detection of multiple gapless nodal lines within -1 eV binding energy, two of them residing along the X-R direction and one formed by polarization-sensitive steep bands lying across the G-M direction. This work unveils the previously unexplored topological electronic structure in NdSbTe providing another distinct platform to understand the Ln-dependent electronic properties in the LnSbTe family of materials.