Anomalous thermal transport under high pressure in boron arsenide
Anomalous thermal transport under high pressure in boron arsenide
复制标题
DOI：
10.1038/s41586-022-05381-x
复制
发表时间：
2022-11-23
期刊：
影响因子：
64.8
通讯作者：
Hu, Yongjie
中科院分区：
文献类型：
--
作者：
Li, Suixuan;Qin, Zihao;Hu, Yongjie
高压代表极端环境，为材料发现提供了机会（1-8）。高静水压力下的热输运已经研究了100多年，迄今为止所有的晶体测量都表明晶格导热系数是单调增加的。在这里，我们报告了新发现的半导体晶体砷化硼的原位热输运测量，并观察到热导率的异常压力依赖性。我们使用超快光学，拉曼光谱和非弹性x射线散射测量来检查光学和声学分支的声子带结构演变，以及在温度和压力高达32千兆帕斯卡的情况下的导热性。利用原子理论，我们将异常高压行为归因于独特声子带结构固有的相互作用高阶非调和物理中的竞争热传导通道。我们的研究验证了从头开始理论计算，我们表明声子动力学-由竞争的三声子和四声子散射过程产生-超出了经典模型的预期，并在普通材料中看到。这项工作将高压光谱学与原子理论相结合，作为探测复杂声子物理的有力方法，并为理解极端性质材料中的微观能量传输提供了基本见解。
High pressure represents extreme environments and provides opportunities for materials discovery(1-8). Thermal transport under high hydrostatic pressure has been investigated for more than 100 years and all measurements of crystals so far have indicated a monotonically increasing lattice thermal conductivity. Here we report in situ thermal transport measurements in the newly discovered semiconductor crystal boron arsenide, and observe an anomalous pressure dependence ofthe thermal conductivity. We use ultrafast optics, Raman spectroscopy and inelastic X-ray scattering measurementsto examine the phonon bandstructure evolution ofthe optical and acoustic branches, as well asthermal conductivity undervaried temperatures and pressures up to 32 gigapascals. Using atomistictheory, we attribute the anomalous high-pressure behaviour to competitive heat conduction channels from interactive high-order anharmonicity physics inherent to the unique phonon bandstructure. Our study verifies ab initio theory calculations and we showthat the phonon dynamics-resulting from competing three-phonon and four-phonon scattering processes-are beyond those expected from classical models and seen in common materials. This work uses high-pressure spectroscopy combined with atomistic theory as a powerful approach to probe complex phonon physics and provide fundamental insights for understanding microscopic energy transport in materials of extreme properties.