Phonons, Localization, and Thermal Conductivity of Diamond Nanothreads and Amorphous Graphene,Nano Letters

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Phonons, Localization, and Thermal Conductivity of Diamond Nanothreads and Amorphous Graphene
Nano Letters ( IF 9.6 ) Pub Date : 2016-07-11 00:00:00 , DOI: 10.1021/acs.nanolett.6b00557
Taishan Zhu ₁ , Elif Ertekin _{1,

2}

Affiliation

Recently, the domains of low-dimensional (low-D) materials and disordered materials have been brought together by the demonstration of several new low-D, disordered systems. The thermal transport properties of these systems are not well-understood. Using amorphous graphene and glassy diamond nanothreads as prototype systems, we establish how structural disorder affects vibrational energy transport in low-dimensional, but disordered, materials. Modal localization analysis, molecular dynamics simulations, and a generalized model together demonstrate that the thermal transport properties of these materials exhibit both similarities and differences from disordered 3D materials. In analogy with 3D, the low-D disordered systems exhibit both propagating and diffusive vibrational modes. In contrast to 3D, however, the diffuson contribution to thermal transport in these low-D systems is shown to be negligible, which may be a result of inherent differences in the nature of random walks in lower dimensions. Despite the lack of diffusons, the suppression of thermal conductivity due to disorder in low-D systems is shown to be mild or comparable to 3D. The mild suppression originates from the presence of low-frequency vibrational modes that maintain a well-defined polarization and help preserve the thermal conductivity in the presence of disorder.

中文翻译：

金刚石纳米线和非晶石墨烯的声子，局部化和热导率

最近，通过演示几种新的低维，无序系统，将低维（低维）材料和无序材料的领域整合在一起。这些系统的热传递特性尚不为人所理解。使用无定形石墨烯和玻璃状金刚石纳米线作为原型系统，我们确定结构无序如何影响低维数但无序的材料中的振动能量传输。模态定位分析，分子动力学模拟和广义模型共同证明，这些材料的热传递性质与无序3D材料既显示出相似之处，也显示出不同之处。与3D相似，低D无序系统同时表现出传播振动模式和扩散振动模式。但是，与3D相比，结果表明，在这些低维系统中，扩散对热传递的贡献可忽略不计，这可能是由于较小尺寸的随机游走的性质存在固有差异所致。尽管没有扩散子，但由于低D系统中的无序而导致的导热系数的抑制是温和的或与3D相当。轻度的抑制来自低频振动模式的存在，该振动模式可保持明确的极化并在出现故障的情况下帮助保持导热性。

更新日期：2016-07-11

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