带孔硅纳米薄膜热整流及声子散射特性研究

本文基于非平衡的分子动力学模拟方法计算了带有三角形孔的硅纳米薄膜的界面热阻特性,结果表明300-1100 K范围内随着热流方向的改变,在含有三角形孔的硅纳米薄膜中存在热整流效应,热整流系数达28％.同时借助于声子波包动力学模拟方法,获得了不同频率下的纵波声子在三角形孔处的散射特性,结果表明纵波声子在散射过程中产生了横波声子,并且从三角形底部向顶部入射的声子能量透射系数比反向时平均低22％.不对称结构引起的声子透射率的差异是引起热整流效应的主要因素.

Thermal rectification and phonon scattering in silicon nanofilm with triangle hole

Thermal rectification has potential applications in the thermal management of electronics and energy saving. Discovering thermal rectification phenomena and understanding the mechanism are very essential. Reported in this paper is the thermal rectification in silicon nanofilm with triangle holes by the non-equilibrium molecular dynamics simulation. The results show that in the silicon nanofilm with triangle holes, the difference in thermal rectification coefficient is around 28% with the variation of heat flow direction in a temperature range from 300 K to 1100 K. The phonon wave packet dynamic simulations indicate that transverse phonons are generated during the scattering of longitudinal phonons in the nanofilms. When the phonon transport direction is reversed, the average phonon energy transmission coefficient is changed by about 22% in all the frequency range. The difference in phonon transmissity, which is caused by asymmetric structure, is regarded as being attributed mainly to the thermal rectification in silicon film with triangle holes.