Visualization of electronic topology in ZrSiSe by scanning tunneling microscopy

This is the authors' abstract. We don't add key points for this paper.

As emerging topological nodal-line semimetals, the family of ZrSiX4pt0ex(X=S,Se,Te) has attracted broad interest in condensed matter physics due to its future applications in spintronics. Here, we apply scanning tunneling microscopy to study the structural symmetry and electronic topology of ZrSiSe. Bias selective topographies are detected and applied to quantify the lattice structure of the ZrSe bilayer. A quasiparticle interference analysis is used to probe the band structure of ZrSiSe. We observe the mergence of two concentric squares ~300 meV above the Fermi level, which shows a nodal-line state consistent with a first principle calculation. An extra surface-state Dirac point is determined ~400 meV below the Fermi level.