Summary: | The presence of one-dimensional (1D) nodal lines, which are formed by band crossing points along a line in the momentum space of materials, is accompanied by several interesting features. However, in order to facilitate experimental detection of the band crossing point signatures, the materials must possess a large linear energy range around the band crossing points. In this work, we focused on a topological metal, YB<sub>2</sub>, with phase stability and a <i>P6/mmm</i> space group, and studied the phonon dispersion, electronic structure, and topological nodal line signatures via first principles. The computed results show that YB<sub>2</sub> is a metallic material with one pair of closed nodal lines in the <i>k<sub>z</sub></i> = 0 plane. Importantly, around the band crossing points, a large linear energy range in excess of 2 eV was observed, which was rarely reported in previous reports that focus on linear-crossing materials. Furthermore, YB<sub>2</sub> has the following advantages: (1) An absence of a virtual frequency for phonon dispersion, (2) an obvious nontrivial surface state around the band crossing point, and (3) small spin–orbit coupling-induced gaps for the band crossing points.
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