Unraveling the Topological Nature of ZrSiTe using Scanning Tunneling Microscopy*

3D topological Dirac semimetals have been a topic of immense study since their experimental realization in 2014. The family of materials ZrSiX (X = S, Se, Te) are topological nodal-line Dirac semimetals, which exhibit a nodal-line band crossing encircling the Γ-point, and two Dirac cones at the X-point protected by a non-symmorphic symmetry. From this family, ZrSiS was the first material to be experimentally studied, and was shown to have two Dirac cones at ± 0.5 V [1]. It was predicted that due to the size difference, substituting S with Te would result in a uniaxial strain along the c-axis, shifting the upper Dirac cone towards the Fermi level [2].

Using low temperature scanning tunneling microscopy and spectroscopy we uncover the surface structure of ZrSiTe, which cleaves easily between ZrTe layers. We observe several unique defects, some of which span multiple lattice sites. Furthermore, by employing quasiparticle interference (QPI), we can resolve the scattering properties of the electrons, and unravel the complex topological nature of the band structure.

[1] Nature Communications 7, 11696 (2016)
[2] New Journal of Physics 18, 125014 (2016)