标题： 电荷密度波诱导的间隙节点线 显示英文标题

标题： Charge density wave induced gapped nodal line

摘要： 我们研究了正方形网络材料中电荷密度波（CDW）序与拓扑节点线态之间的相互作用。 我们的吉尔伯特-兰道理论预测了一种CDW不稳定性，通常会在费米能级打开一个间隙，同时保持节点线交叉。 然而，当费米能级接近节点线时，节点线处的态密度会减少，当CDW矢量$\mathbf{Q}$趋近于零时，最终消失。 正好在$\mathbf{Q} = 0$时，序参量明确破坏了保护节点线的滑移对称性，这允许间隙的打开。 然而，对于小但有限的$\mathbf{Q}$，即使滑移对称性被保持，节点线也可能在实验分辨率内消失。 我们的结果为最近的实验观察提供了一个一致的解释。 显示英文摘要

摘要： We investigate the interplay between charge density wave (CDW) order and topological nodal-line states in square-net materials. Our Ginzburg-Landau theory predicts a CDW instability that generically opens a gap at the Fermi energy while preserving the nodal line crossing. However, as the Fermi level approaches the nodal line, the density of states at the nodal line decreases, eventually disappearing as the CDW vector $\mathbf{Q}$ goes to zero. Exactly at $\mathbf{Q} = 0$, the order parameter explicitly breaks the glide symmetry protecting the nodal line, which allows a gap to open. Yet, for small but finite $\mathbf{Q}$, the nodal line may vanish within experimental resolution even when the glide symmetry is preserved. Our results provide a consistent explanation for recent experimental observations.