Phonon hydrodynamics in two-dimensional materials
Phonon hydrodynamics in two-dimensional materials
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DOI：
10.1038/ncomms7400
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发表时间：
2015-03-01
影响因子：
16.6
通讯作者：
Marzari, Nicola
中科院分区：
文献类型：
--
作者：
Cepellotti, Andrea;Fugallo, Giorgia;Marzari, Nicola
二维热传导展示了许多与石墨烯及相关材料的科学理解和技术应用关键相关的迷人现象。在这里，我们使用密度泛函微扰理论和玻尔兹曼输运方程的精确变分解，从第一原理出发全面研究石墨烯、氮化硼、二硫化钼以及功能化衍生物石墨烷和氟石墨烯中的声子输运和热导率。在所有这些材料中，与典型的三维固体不同，正常过程在远高于低温条件的 Umklapp 散射中占主导地位，延伸到室温及更高温度。结果，泊肃叶和齐曼流体动力学出现了新的机制，迄今为止通常仅限于超低温，表征了普通条件下的输运。最值得注意的是，其中一些二维材料允许波状热扩散，在石墨烯、氮化硼和石墨烷中在室温及以上温度下存在第二声。
The conduction of heat in two dimensions displays a wealth of fascinating phenomena of key relevance to the scientific understanding and technological applications of graphene and related materials. Here, we use density-functional perturbation theory and an exact, variational solution of the Boltzmann transport equation to study fully from first-principles phonon transport and heat conductivity in graphene, boron nitride, molybdenum disulphide and the functionalized derivatives graphane and fluorographene. In all these materials, and at variance with typical three- dimensional solids, normal processes keep dominating over Umklapp scattering well-above cryogenic conditions, extending to room temperature and more. As a result, novel regimes emerge, with Poiseuille and Ziman hydrodynamics, hitherto typically confined to ultra-low temperatures, characterizing transport at ordinary conditions. Most remarkably, several of these two-dimensional materials admit wave-like heat diffusion, with second sound present at room temperature and above in graphene, boron nitride and graphane.