单晶Ge纳米薄膜面向热导率的分子动力学模拟

Molecular Dynamics Simulation of In-Plane Thermal Conductivity for Ge Single-Crystal Thin Films

利用非平衡分子动力学模拟方法研究了单晶Ge薄膜的厚度以及温度对其面向热导率的影响规律。针对单晶Ge薄膜的结构特点和导热机制,采用Stillinger-Weber势能模型描述Ge粒子间的相互作用,并且建立面向稳态热传导模型。模拟结果显示,单晶Ge薄膜面向热导率具有明显尺寸效应,随薄膜厚度的增加而增大,随温度的升高而减小。与法向热导率的模拟结果进行比较,证明单晶Ge薄膜热导率具有各向异性的特点。

The effects of thickness and temperature on the in-plane thermal conductivities of germanium single-crystal thin films have been investigated by a non-equilibrium molecular dynamics（NEMD） simulation method. The Stillinger-Weber potential model was employed to describe the interaction between atoms in the germanium single-crystal thin films. Taking structural characteristics and heat transfer mechanism of the germanium single-crystal thin films, a steady heat transfer model was framed. The results of calculations demonstrate that the in-plane thermal conductivities of germanium single-crystal thin films show an obvious size effect, which increases with increasing of thin film thickness and decreases with increasing of temperature. Comparing with the cross-plane thermal conductivity, the simulation results prove that the thermal conductivities of germanium single-crystal thin films have anisotropic characteristics.