为研究电介质薄膜中的导热机制以及薄膜厚度对导热系数的影响 ,以氩的 FCC晶体为模型 ,采用分子动力学方法计算了厚度约为 2～ 10 nm的薄膜的法向导热系数。计算得到对应于 12 0 K的薄膜导热系数显著低于大体积实验值 ,并随薄膜厚度的减小而降低 ;即纳米薄膜的晶格导热系数具有明显的尺寸效应。当薄膜厚度减小至纳米量级时 ,即使在较高温情况下 1.3ΘD,晶体边界对声子的散射也将起重要作用。对氩晶体分别选取了 L ennard- Jones作用势和一种软球作用势 ,考察了不同势能模型对于模拟结果的影响 In order to study the thermal conduction mechanism and the effect of film thickness on the thermal conductivity in dielectric thin films, the normal thermal conductivity of thin films with thickness of 2 ~ 10 nm was calculated by molecular dynamics method using the argon FCC crystal as a model. The calculated thermal conductivity of the films corresponding to 12 0 K is significantly lower than the experimental value of large volume, and decreases with the decrease of the film thickness; that is, the lattice thermal conductivity of the nanostructured films has obvious size effect. When the film thickness is reduced to the order of nanometers, the crystal boundary will play an important role in phonon scattering even at higher temperatures of 1.3ΘD. The L ennard-Jones potential and a kind of softball potential are respectively selected for the argon crystal and the effects of different potential models on the simulation results are investigated