热导率
石墨
声子
钻石
材料科学
热扩散率
凝聚态物理
各向异性
石墨烯
大气温度范围
热传导
热力学
复合材料
纳米技术
光学
物理
作者
Yo Machida,Nayuta Matsumoto,T. Isono,Kamran Behnia
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:2020-01-17
卷期号:367 (6475): 309-312
被引量:101
标识
DOI:10.1126/science.aaz8043
摘要
Allotropes of carbon, such as diamond and graphene, are among the best conductors of heat. We monitored the evolution of thermal conductivity in thin graphite as a function of temperature and thickness and found an intimate link between high conductivity, thickness, and phonon hydrodynamics. The room temperature in-plane thermal conductivity of 8.5-micrometer-thick graphite was 4300 watts per meter-kelvin-a value well above that for diamond and slightly larger than in isotopically purified graphene. Warming enhances thermal diffusivity across a wide temperature range, supporting partially hydrodynamic phonon flow. The enhancement of thermal conductivity that we observed with decreasing thickness points to a correlation between the out-of-plane momentum of phonons and the fraction of momentum relaxing collisions. We argue that this is due to the extreme phonon dispersion anisotropy in graphite.
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