Phonon Dispersion in <100>Si Nanowire Covered with Si02 Film Calculated by Molecular Dynamics Simulation
Phonon Dispersion in <100>Si Nanowire Covered with Si02 Film Calculated by Molecular Dynamics Simulation
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分子动力学模拟计算覆盖SiO2薄膜的<100>Si纳米线中的声子色散
DOI：
10.1149/05009.0673ecst
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Takanobu Watanabe
中科院分区：
文献类型：
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作者：
西川綾;寺口昌宏;青木俊樹;金子隆司;Takanobu Watanabe
采用< 100>一个真实的原子模型，计算了硅纳米线（SiNW）中的声子色散关系。我们利用分子动力学模拟方法，通过对原子轨道的时空傅里叶变换计算动力学结构因子，并提取声子色散关系。虽然体色散关系在整体上保持在硅纳米线，声学声子分支扩散到无法识别，这被认为是在硅纳米线的热导率退化的起源。由于外氧化膜引起的晶格应变，横光学模也出现了红移。这些结果提供了一个立足点，估计的电子-声子散射率和热输运过程中的现实硅纳米线。
The phonon dispersion relation in< 100> Si nanowire (SiNW) is calculated by employing a realistic atomistic model surrounded by thin SiO2 layers. We performed molecular dynamics simulation to calculate the dynamical structure factor by the space-time Fourier transform of atomic trajectories, and extracted the phonon dispersion relations. Although the bulk dispersion relations are maintained in the SiNWs on the whole, acoustic phonon branches are diffused beyond recognition, which is considered as the origin of the thermal conductivity degradation in SiNWs. A red shift of the transverse optical mode also appears probably due to the lattice strain induced by the outer oxide film. These results provide a foothold to estimate the electron-phonon scattering rates and the heat transport processes in realistic SiNWs.