Observation of multiple nodal-lines in SmSbTe

Within the family of ZrSiS-type 111 materials, the  LnSbTe (Ln = lanthanide elements)-type materials are attracting research interests in recent times because of the possible correlation effects and magnetism arising from the 4f electrons of the lanthanides, which can provide an important platform  to study the linking between topology, magnetism, and correlation. In this talk, we present the systematic report of the electronic structure of SmSbTe by utilizing angle-resolved photoemission spectroscopy in conjunction with first-principles calculations, transport, and magnetic measurements. Our experimental results identify multiple Dirac nodes forming the nodal-lines along the Γ – M and Z – R directions in the bulk Brillouin zone (BZ) as predicted by our theoretical calculations. A surface Dirac-like state that arises from the square net plane of the Sb atoms is also observed at the X point of the surface BZ. Our study highlights SmSbTe as a promising candidate to understand the topological electronic structure of LnSbTe materials.