  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.
