Effect of long- and short-range order on SiGe alloy thermal conductivity: Molecular dynamics simulation
Effect of long- and short-range order on SiGe alloy thermal conductivity: Molecular dynamics simulation
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长程和短程有序对 SiGe 合金热导率的影响：分子动力学模拟
DOI：
10.1103/physrevb.91.180302
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
P. Norris
中科院分区：
文献类型：
--
作者：
Christopher H. Baker;P. Norris
我们利用分子动力学模拟报告了长程有序和短程有序对一种Si0.5Ge0.5模型合金的热导率和模式弛豫时间的作用。所有相互作用都采用了斯廷格勒 - 韦伯势，并且Si和Ge原子仅在质量上有所不同。模拟合金是使用蒙特卡罗方法生成的，以将短程有序与长程有序解耦。热导率几乎完全由合金的最近邻短程有序决定。短程有序时在3到6太赫兹之间模式弛豫时间的变化以及观察到的$f^{-2}$幂律趋势表明，短程有序降低了低频模式的非谐散射率。在质量无序散射主导其热导率的程度上，短程有序对热导率的影响趋势可能会转移到实际的Si0.5Ge0.5和其他半导体合金中。
We report the role of long- and short-range order on the thermal conductivity and mode relaxation times of a model Si0.5Ge0.5 alloy using molecular dynamics simulation. All interactions used the Stillinger-Weber potential and the Si and Ge atoms differed only by their mass. The simulated alloys were generated using a Monte Carlo approach to decouple the short-range order from the long-range order. The thermal conductivity is almost entirely determined by the alloy’s nearest-neighbor short-range order. Changes to the mode relaxation times between ! 3a nd! 6 THz upon short-range ordering, and the observed f " 2 power law trend, suggest that short-range ordering reduces the anharmonic scattering rate of low frequency modes. The trend of thermal conductivity with short-range order may be transferred to real Si0.5Ge0.5 and other semiconductor alloys to the extent that scattering from mass disorder dominates their thermal conductivities.