论文标题
tlinte $ _2 $的异常晶格热传输的微观机制
Microscopic mechanism of unusual lattice thermal transport in TlInTe$_2$
论文作者
论文摘要
我们使用统一的晶格热传输理论研究了tlinte $ _2 $的超级晶格导热率（$κ_l$）的微观机制，其温度依赖性使用了统一的晶格热传输理论，该理论考虑了构成粒子样繁殖产生的贡献以及音孔的波浪样隧道。虽然我们使用Peierls-Boltzmann传输方程（PBTE）来计算类似粒子的贡献（$κ_l$（PBTE）），但我们明确地计算了在供应范围内供应的第一个Principles函数框架内的热量型操作员的偏置（OD）组成部分，以确定$κ_____的waver（$κ___）。在每个温度下，t，我们使用自洽的声子理论（包括四分之一的呼吸态度）对声子频率重新归一化，并利用它们来计算$κ_l$（pbte）和$κ_l$（OD）。随着$κ_l$（PBTE），$κ_l$（OD）的总包含以及其他晶粒散射，我们的计算成功地重现了实验结果。我们的分析表明，tlinte $ _2 $（a）强烈的高四分之一的非谐声强烈硬化了低能量的声子分支，（b）减小了有限t的三个子散射过程，并且（c）恢复了比t $^{ - 1} $衰减的弱$κ____$κ__l$ bet $^{-1} $。
We investigate the microscopic mechanism of ultralow lattice thermal conductivity ($κ_l$) of TlInTe$_2$ and its weak temperature dependence using a unified theory of lattice heat transport that considers contributions arising from the particle-like propagation as well as wave-like tunneling of phonons. While we use the Peierls-Boltzmann transport equation (PBTE) to calculate the particle-like contributions ($κ_l$(PBTE)), we explicitly calculate the off-diagonal (OD) components of the heat-flux operator within a first-principles density functional theory framework to determine the contributions ($κ_l$(OD)) arising from the wave-like tunneling of phonons. At each temperature, T, we anharmonically renormalize the phonon frequencies using the self-consistent phonon theory including quartic anharmonicity, and utilize them to calculate $κ_l$(PBTE) and $κ_l$(OD). With the combined inclusion of $κ_l$(PBTE), $κ_l$(OD), and additional grain-boundary scatterings, our calculations successfully reproduce the experimental results. Our analysis shows that large quartic anharmonicity of TlInTe$_2$ (a) strongly hardens the low-energy phonon branches, (b) diminishes the three-phonon scattering processes at finite T, and (c) recovers the weaker than T$^{-1}$ decay of the measured $κ_l$.
