Electronic Structure of Quasi-1D Topological Nodal-line Semimetals

Nodal line semimetals (NLSMs) are symmetry-protected topological materials with Dirac/Weyl-type band crossings that extend into loops or lines in reciprocal space. These materials often show novel transport properties, including highly-anisotropic magnetoresistance, quantum oscillations, and non-zero Berry curvatures [1-2]. Using angle-resolved photoemission spectroscopy (ARPES) and density-functional-theory calculations, we have shown that quasi-1D structure tellurides TaXTe₅ (X = Ni, Pt) are NLSMs, hosting Dirac-like surface states and nodal lines with quasi-2D electronic structures. These Dirac-like states exhibit complex dichroism in ARPES. We have also shown that when electrons are doped into these systems, the Fermi surfaces change dramatically and flat-band-like electronic states appear near the Fermi energy (E_F). The energy position of the flat-band is also highly tunable by controlling the doping. Flat-bands around E_F may enhance electronic correlations that can lead to novel transport properties.

[1] Chen et al., Phys. Rev. B 103, 035105 (2021)

[2] Jiao et al., Phys. Rev. B 103, 125150 (2021)