Symmetry-enforced straight nodal-line phonons
Symmetry-enforced straight nodal-line phonons
Based on first-principles calculations and effective model analysis, all possible straight nodal-line (NL) phonons in symmorphic and nonsymmorphic space groups are uncovered. A classification of two-band $\mathbf{k}\ifmmode\cdot\else\textperiodcentered\fi{}\mathbf{p}$ models at an arbitrary point on the NLs is carried out, and these NL phonons are found to locate along the high-symmetry lines …