多壁碳纳米管与基体之间界面热输运分子动力学模拟

Molecular dynamics simulation of thermal transport along the interface between multi-wall carbon nanotube and its substrate

碳纳米管与基体之间的热耦合对纳米结构界面热输运起主导作用。采用非平衡态分子动力学模拟了垂直生长多壁碳纳米管与Si基体之间的热耦合,得到界面热导的温度效应和作用力效应并利用声子输运理论进行了分析。低温下多壁碳纳米管与Si之间声子的态密度匹配较好,界面热输运能力主要取决于界面两侧低频声子的耦合振动,高温下近界面区域内热输运能力受高频声子的非弹性散射影响而逐渐增强。随着范德瓦尔斯力增强,界面热导线性增大。

Thermal coupling between carbon nanotube （CNT） and its substrate plays a predominant role in thermal transport along their interface. We employ nonequilibrium molecular dynamics （NEMD） to simulate the thermal coupling between CNT and its Si substrate, We further acquire the temperature and force effects of thermal boundary conductance and analyze them with phonon transport theory. Phonon state density between multi-wall carbon nanotube （MWNT） and Si well matches at low temperature. Interface thermal transport ability depends on low-frequency phonon coupling resonance scattering at two sides of the interface. Thermal transport ability at near interface region is affected by phonon inelastic scattering. Thermal boundary conductance linearly increases with the increase of van der Waals force.