Heat conduction of single-walled carbon nanotube isotope superlattice structures: A molecular dynamics study
Heat conduction of single-walled carbon nanotube isotope superlattice structures: A molecular dynamics study
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DOI：
10.1103/physrevb.74.155401
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发表时间：
2006-10-01
影响因子：
3.7
通讯作者：
Maruyama, Shigeo
中科院分区：
文献类型：
--
作者：
Shiomi, Junichiro;Maruyama, Shigeo
通过经典分子动力学模拟研究单壁碳纳米管（SWNT）同位素超晶格的热传导。超晶格结构是通过交替连接不同质量的单壁碳纳米管而形成的。在改变超晶格周期时，确定了具有最小有效导热率的临界值，其中主导物理从区域折叠效应转变为晶格界面的热边界电阻。交叉机制用能量密度谱来解释，可以清楚地观察到区域折叠效应。结果表明，临界超晶格周期厚度取决于扩散弹道声子的平均自由程分布。超晶格结构的热导率降低优于一维合金结构，尽管最小热导率仍略高于二维同位素随机混合获得的值。
Heat conduction of single-walled carbon nanotubes (SWNTs) isotope superlattice is investigated by means of classical molecular dynamics simulations. Superlattice structures were formed by alternately connecting SWNTs with different masses. On varying the superlattice period, the critical value with minimum effective thermal conductivity was identified, where dominant physics switches from zone-folding effect to thermal boundary resistance of lattice interface. The crossover mechanism is explained with the energy density spectra where zone-folding effects can be clearly observed. The results suggest that the critical superlattice period thickness depends on the mean free path distribution of diffusive-ballistic phonons. The reduction of the thermal conductivity with superlattice structures beats that of the one-dimensional alloy structure, though the minimum thermal conductivity is still slightly higher than the value obtained by two-dimensional random mixing of isotopes.