ZrGeSe is one of the most well-known topological nodal-line semimetals, which possesses linearly dispersive electronic bands near the Fermi surface. However, the lattice-dynamics study and its interaction with the electronic system have not been investigated. We employed the inelastic neutron-scattering method to study the lattice dynamics of ZrGeSe single crystals. The measured acoustic phonon dispersions were compared with lattice-dynamics calculations, with an overall good agreement with theory; however, both the longitudinal and the transverse acoustic phonon dispersions along the ($q00$) directions demonstrate significant softening, unexpectedly in contrast with the theoretical predictions. Complementary ab initio molecular dynamics simulations indicate an anomalous temperature dependency in the vibrational spectroscopy. We show that strong electron-phonon coupling exists along the Γ-$M-X$ directions and argue that the phonon softening is induced by such electron-phonon coupling.

中文翻译：

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拓扑节线半金属 ZrGeSe 中的声子软化和电子声子耦合

ZrGeSe是最著名的拓扑节线半金属之一，在费米表面附近具有线性色散电子带。然而，晶格动力学研究及其与电子系统的相互作用尚未得到研究。我们采用非弹性中子散射方法研究了ZrGeSe单晶的晶格动力学。将测量的声子色散与晶格动力学计算进行了比较，总体上与理论吻合良好；然而，纵向和横向声声子色散都沿着（$q00$）方向表现出显着的软化，出乎意料地与理论预测相反。互补的从头算分子动力学模拟表明振动光谱中存在异常的温度依赖性。我们证明沿着 Γ- 存在强电子-声子耦合$\mathrm{中号}-X$方向并认为声子软化是由这种电子-声子耦合引起的。