Multiple Symmetry-Protected Dirac Nodal Lines in A Quasi-One-Dimensional Semimetal

TL;DR

This paper reports the discovery of multiple symmetry-protected Dirac nodal lines in a quasi-one-dimensional semimetal TaNiTe5, revealing new topological features arising from reduced dimensionality and nonsymmorphic symmetry.

Contribution

It demonstrates the existence of robust nodal-line semimetal phases in a quasi-one-dimensional material, combining experimental and theoretical methods to uncover novel topological band structures.

Findings

Identification of multiple Dirac-type nodal lines with four-fold degeneracy

Experimental validation via angle-resolved photoemission spectroscopy

First-principles calculations confirming the topological nature

Abstract

Nodal-line semimetals (NLSMs) contains Dirac/Weyl type band-crossing nodes extending into shapes of line, loop and chain in the reciprocal space, leading to novel band topology and transport responses. Robust NLSMs against spin-orbit coupling typically occur in three-dimensional materials with more symmetry operations to protect the line nodes of band crossing, while the possibilities in lower-dimensional materials are rarely discussed. Here we demonstrate robust NLSM phase in a quasi-one-dimensional nonmagnetic semimetal TaNiTe5. Combining angle-resolved photoemission spectroscopy measurements and first-principles calculations, we reveal how reduced dimension can interact with nonsymmorphic symmetry and result into multiple Dirac-type nodal lines with four-fold degeneracy. Our findings suggest rich physics and application in (quasi-)one-dimensional topological materials and call for further investigation on the interplay between the quantum confinement and nontrivial band topology.