Observations of nodal lines in the topological semimetal ZrSnTe

Performing angle-resolved photoemission spectroscopy(ARPES) and theoretical calculations for ZrSnTe, we find a nodal line in the k_x-k_y plane with a tiny gap and two nodal lines without gaps along the kzdirection. The constant energy contours are plotted in the k_x-k_y plane at a photon energy of 30 e V to examine the gapping feature of the nodal line. In addition, we depict the band dispersions along the Γ-M and Γ-X directions from the ARPES images at photon energies ranging from 24 to 40 e V. The k_z mapping confirms the presence of stable Dirac points with obvious kzdependences along the M-A and X-R directions. In this paper, we report the two types of nodal lines associated with the theoretical local-density approximation calculations, broadening the horizons of nodal-line semimetal research.