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 k(z) direction. The constant energy contours are plotted in the k(x)-k(y) plane at a photon energy of 30 eV to examine the gapping feature of the nodal line. In addition, we depict the band dispersions along the Gamma -M and Gamma -X directions from the ARPES images at photon energies ranging from 24 to 40 eV. The k(z) mapping confirms the presence of stable Dirac points with obvious k(z) dependences 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.