Particlelike Phonon Propagation Dominates Ultralow Lattice Thermal Conductivity in Crystalline Tl_{3}VSe_{4}.,Physical Review Letters

当前位置： X-MOL 学术 › Phys. Rev. Lett. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Particlelike Phonon Propagation Dominates Ultralow Lattice Thermal Conductivity in Crystalline Tl_{3}VSe_{4}.
Physical Review Letters ( IF 8.1 ) Pub Date : 2020-02-14 , DOI: 10.1103/physrevlett.124.065901
Yi Xia ₁ , Koushik Pal ₁ , Jiangang He ₁ , Vidvuds Ozoliņš _{2,

3} , Chris Wolverton ₁

Affiliation

We investigate the microscopic mechanisms of ultralow lattice thermal conductivity (κ_{l}) in Tl_{3}VSe_{4} by combining a first principles density functional theory based framework of anharmonic lattice dynamics with the Peierls-Boltzmann transport equation for phonons. We include contributions of the three- and four-phonon scattering processes to the phonon lifetimes as well as the temperature dependent anharmonic renormalization of phonon energies arising from an unusually strong quartic anharmonicity in Tl_{3}VSe_{4}. In contrast to a recent report by Mukhopadhyay et al. [Science 360, 1455 (2018)SCIEAS0036-807510.1126/science.aar8072] which suggested that a significant contribution to κ_{l} arises from random walks among uncorrelated oscillators, we show that particlelike propagation of phonon excitations can successfully explain the experimentally observed ultralow κ_{l}. Our findings are further supported by explicit calculations of the off-diagonal terms of the heat current operator, which are found to be small and indicate that wavelike tunneling of heat carrying vibrations is of minor importance. Our results (i) resolve the discrepancy between the theoretical and experimental κ_{l}, (ii) offer new insights into the minimum κ_{l} achievable in Tl_{3}VSe_{4}, and (iii) highlight the importance of high order anharmonicity in low-κ_{l} systems. The methodology demonstrated here may be used to resolve the discrepancies between the experimentally measured and the theoretically calculated κ_{l} in skutterides and perovskites, as well as to understand the glasslike κ_{l} in complex crystals with strong anharmonicity, leading towards the goal of rational design of new materials.

中文翻译：

类粒子声子的传播主导着晶体Tl_ {3} VSe_ {4}中的超低晶格导热率。

通过结合基于第一原理密度泛函理论的非谐晶格动力学框架和声子的Peierls-Boltzmann输运方程，我们研究了Tl_ {3} VSe_ {4}中超低晶格导热系数（κ_{l}）的微观机理。我们包括三和四声子散射过程对声子寿命的贡献，以及由于Tl_ {3} VSe_ {4}中异常强的四次非谐性而引起的声子能量的温度依赖性非谐重归一化。与Mukhopadhyay等人的最新报告相反。[Science 360，1455（2018）SCIEAS0036-807510.1126 / science.aar8072]提出，对κ_{l}的重要贡献来自于不相关的振荡器之间的随机游动，我们表明，声子激发的类粒子传播可以成功地解释实验观察到的超低κ_{l}。我们的发现进一步得到了对热电流算子的非对角线项的显式计算的支持，该计算对角线项很小，这表明载热振动的波状隧道效应次要。我们的结果（i）解决了理论和实验κ_{l}之间的差异，（ii）提供了对Tl_ {3} VSe_ {4}中可达到的最小κ_{l}的新见解，并且（iii）强调了低κ_{l}系统中的高阶非谐性。此处演示的方法可用于解决实验测量和理论计算的skutterides和钙钛矿中κ_{l}之间的差异，

更新日期：2020-02-14

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11