论文标题
声子在拓扑相转换附近软化
Phonon softening near topological phase transitions
论文作者
论文摘要
当电子带更改其拓扑特性时，发生拓扑相变（通常以带隙的关闭）。虽然已经对拓扑相变对电子和光学性质的影响进行了广泛的研究，但其对语音性质的影响和热传输仍未开发。在这项工作中，我们使用第一原理模拟表明某些声子模式在拓扑相变附近显着软化，从而导致声子散射增加并降低晶格导热率。我们使用两个模型系统证明了这种效果：$ \ rm Zrte_5 $中的压力诱导的拓扑相变和化学成分诱导的拓扑相变为$ \ rm {hg_ {1-x} cd_ {x} cd_ {x} te} $。我们将声子软化归因于与带隙关闭相关的新兴kohn异常。我们的研究揭示了电子带结构与晶格不稳定性之间的牢固联系，并为控制固体的热传导打开了潜在的方向。
Topological phase transitions occur when the electronic bands change their topological properties, typically featuring the closing of the bandgap. While the influence of topological phase transitions on electronic and optical properties has been extensively studied, its implication on phononic properties and thermal transport remains unexplored. In this work, we use first-principles simulations to show that certain phonon modes are significantly softened near topological phase transitions, leading to increased phonon-phonon scattering and reduced lattice thermal conductivity. We demonstrate this effect using two model systems: pressure-induced topological phase transition in $\rm ZrTe_5$ and chemical composition induced topological phase transition in $\rm{Hg_{1-x}Cd_{x}Te}$. We attribute the phonon softening to emergent Kohn anomalies associated with the closing of the bandgap. Our study reveals the strong connection between electronic band structures and lattice instabilities and opens up a potential direction towards controlling heat conduction in solids.
