电介质薄膜中的稳态导热与法向导热系数的尺寸效应

Steady-State Heat Conduction and Size Effect of Normal Thermal Conductivity in Thin Dielectric Films

通过非平衡分子动力学 (NEMD)模拟预报了纳米电介质薄膜的法向导热系数 .采用各向异性的非平衡分子动力学方案模拟了固体氩薄膜中垂直于膜平面的稳态导热 ,考察了对应于平均温度为 4 5K的薄膜法向导热系数与膜厚度的关系 .在氩薄膜厚度为 2 12 4～ 10 62nm的范围内 ,薄膜法向导热系数显著低于相同温度下的大体积材料的实验值 ,并随膜厚度的减小而降低 ,具有显著的尺寸效应 .在弛豫时间近似条件下得到的声子Boltzmann输运方程的近似解表明 。

Non-equilibrium molecular dynamics (NEMD) simulations have been performed to explore the normal thermal conductivity of nanoscale thin dielectric films. The inhomogeneous NEMD scheme is employed to model heat conduction across argon thin films. At an average temperature of 45 K, the size effect of thermal conductivity across solid argon nano-films with a thickness range of 2.124-10.62 nm is reported. A solution of the phonon Boltzmann transport equation under the relaxation time approximation is used to account for the size effect of the lattice thermal conductivity based on phonon-boundary scattering.