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首页> 外文期刊>Journal of Heat Transfer >Thermal Conductivity of Individual Single-Wall Carbon Nanotubes
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Thermal Conductivity of Individual Single-Wall Carbon Nanotubes

机译：单个单壁碳纳米管的导热系数

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Despite the significant amount of research on carbon nanotubes, the thermal conductivity of individual single-wall carbon nanotubes has not been well established. To date only a few groups have reported experimental data for these molecules. Existing molecular dynamics simulation results range from several hundred to 6600 W/m K and existing theoretical predictions range from several dozens to 9500 W/m K. To clarify the several-order-of-magnitude discrepancy in the literature, this paper utilizes molecular dynamics simulation to systematically examine the thermal conductivity of several individual (10, 10) single-wall carbon nanotubes as a function of length, temperature, boundary conditions and molecular dynamics simulation methodology. Nanotube lengths ranging from 5 nm to 40 nm are investigated. The results indicate that thermal conductivity increases with nanotube length, varying from about 10 W/m to 375 W/m K depending on the various simulation conditions. Phonon decay times on the order of hundreds of fs are computed. These times increase linearly with length, indicating ballistic transport in the nanotubes. A simple estimate of speed of sound, which does not require involved calculation of dispersion relations, is presented based on the heat current autocorrelation decay. Agreement with the majority of theoretical/computational literature thermal conductivity data is achieved for the nanotube lengths treated here. Discrepancies in thermal conductivity magnitude with experimental data are primarily attributed to length effects, although simulation methodology, stress, and intermolecular potential may also play a role. Quantum correction of the calculated results reveals thermal conductivity temperature dependence in qualitative agreement with experimental data.
机译：尽管对碳纳米管进行了大量研究，但尚未很好地确定单个单壁碳纳米管的热导率。迄今为止，只有少数小组报告了这些分子的实验数据。现有的分子动力学模拟结果范围从几百到6600 W / m K，现有的理论预测范围从几十到9500 W / mK。为澄清文献中的几个数量级差异，本文利用分子动力学模拟以系统地检查几种单独的（10、10）单壁碳纳米管的导热系数，该导热系数是长度，温度，边界条件和分子动力学模拟方法的函数。研究了从5 nm到40 nm的纳米管长度。结果表明，热导率随纳米管长度的增加而增加，取决于各种模拟条件，其范围从约10 W / m到375 W / mK。计算出声子的衰减时间约为数百fs。这些时间随长度线性增加，表明在纳米管中的弹道传输。基于热电流自相关衰减，提出了一种简单的声速估计方法，不需要进行色散关系的计算。对于这里处理的纳米管长度，与大多数理论/计算文献的热导率数据达成了一致。尽管模拟方法，应力和分子间电势也可能起一定作用，但导热系数与实验数据的差异主要归因于长度效应。计算结果的量子校正显示出与实验数据定性一致的热导率温度依赖性。

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