氩晶体薄膜法向热导率的分子动力学模拟

结合卫星“微型核”的特点，研究电介质薄膜中的导热机理以及薄膜厚度对导热系数的影响.以结构较为简单、具有可靠势能函数，实验数据较为丰富和可靠的氩的(fcc)晶体为模型,采用平衡分子动力学方法(EMD)和各向异性非平衡分子动力学方法(NEMD)计算了氩晶体及其法向薄膜的热导率,并与实验结果进行比较.模拟结果表明，氩晶体纳米薄膜的热导率显著小于对应大体积晶体的实验值，具有明显的尺寸效应.在氩薄膜厚度为2.124—5.310nm的模拟范围内,薄膜的法向热导率随着薄膜厚度的增加而呈近似线性增加.关键词：热导率纳米薄膜尺寸效应平衡分子动力学非平衡分子动力学

Molecular dynamics simulation on the out-of plane thermal conductivity of argon crystal thin films

Part of results of research on satellite heat control under the Harvest Project of the National 973 Program is reported.In accordance with the “minimized nucleus” requirement of the satellite,the thermal conductivity of the dielectric FCC argon-crystal nano-film in the normal direction is predicted using the equilibrium molecular dynamic (EMD) and non-equilibrium molecular dynamic (NEMD) methods. The calculated results are compared with the experimental value of the bulk cryastal.Our calculation shows that the thermal conductivity of the thin films is much lower than that of its bulk conterpart,and the size-effect is significant;it increses nearly linearly with increasing thickness in the thickness range of 2.124—5.310nm.