Phonon softening near topological phase transitions
Phonon softening near topological phase transitions
复制标题
DOI：
10.1103/physrevb.102.235428
复制
发表时间：
2020-11
影响因子：
3.7
通讯作者：
Shengying Yue;B. Deng;Yanming Liu;Y. Quan;Runqing Yang;Bolin Liao
中科院分区：
文献类型：
--
作者：
Shengying Yue;B. Deng;Yanming Liu;Y. Quan;Runqing Yang;Bolin Liao
当电子带改变其拓扑性质时，拓扑相变就发生了，典型的特征是带隙的闭合。虽然拓扑相变对电子和光学性质的影响已被广泛研究，但其对声子性质和热输运的影响仍未被探索。在这项工作中，我们使用第一性原理模拟来表明某些声子模式在拓扑相变附近显着软化，导致声子-声子散射增加和晶格导热系数降低。我们用两个模型体系证明了这种效应：$\rm ZrTe_5$中的压力诱导拓扑相变和$\rm{Hg_{1-x}Cd_{x}Te}$中的化学成分诱导拓扑相变。我们将声子软化归因于与带隙闭合相关的Kohn异常。我们的研究揭示了电子能带结构与晶格不稳定性之间的紧密联系，并为控制固体中的热传导开辟了一个潜在的方向。
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.