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arXiv · 2102.07114

Straight nodal-line phonons in symmorphic space groups

Guang Liu·Yuanjun Jin·Zhongjia Chen·Hu Xu
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Abstract

Based on first-principles calculations and effective model analysis, all possible straight nodal-line phonons in symmorphic space groups are uncovered. A classification of two-band ${\textbf{k}}\cdot {\textbf{p}}$ models at an arbitrary point on the nodal lines is carried out, and these nodal-line phonons are found to locate along the high symmetry lines of the Brillouin zone. According to our classification, there are two types of nodal-line phonons in symmorphic space groups. The first type possesses a linear dispersion perpendicular to the nodal lines, while the second type exhibits a quadratic dispersion. The underlying mechanisms are revealed by symmetry analysis, and the types of nodal-line phonons can be distinguished through the little group of the high symmetry lines. Our work not only classifies nodal-line phonons but also provides guidance to search for topological nodal lines in bosonic systems.

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Guang Liu, Yuanjun Jin, Zhongjia Chen, Hu Xu. 2021-02-14. Straight nodal-line phonons in symmorphic space groups. https://doi.org/10.1103/physrevb.104.024304

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