2D Fermi surface and topological states in the CDW compound TaTe₄

Transition metal chalcogenides have attracted considerable attention of the scientific community during the last few years, exhibiting remarkable effects such as topological non-trivial states and induced superconductivity. TaTe₄ is a quasi-1D tetrachalcogenide that presents a CDW instability caused by a periodic lattice distortion, forming a commensurately modulated structure stable in a wide temperature range.
Recent studies have reported a metallic response to transport measurements presenting a resistivity plateau at low temperature [1], characteristic of topological surface states. An large magnetoresistance was also reported [1], presenting quantum oscillations with the angle dependence of a two-dimensional Fermi surface. More recently, pressure-induced superconductivity was also achieved in this material [2].
We performed Angular-resolved Photoemission spectroscopy (ARPES) measurements in TaTe₄ single crystals grown by a self-flux technique. Contrary to previous ARPES results [3], our findings showed a coexistence of CDW and topological features in a two-dimensional anisotropic Fermi surface.

[1] X. Luo et al. Appl. Phys. Lett. 110, 9 (2017).
[2] Y. Yuan et al. Adv. Electron. Mater. 6, 3 (2020).
[3] F. Zwick et al. Phys. Rev. B 59, 11 (1999).