Effects of medium range order on propagon thermal conductivity in amorphous silicon
Effects of medium range order on propagon thermal conductivity in amorphous silicon
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DOI：
10.1063/1.5124821
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发表时间：
2020-01-31
影响因子：
3.2
通讯作者：
Lee, Sangyeop
中科院分区：
文献类型：
--
作者：
Hashemi, Amirreza;Babaei, Hasan;Lee, Sangyeop
讨论了传播子对非晶硅热导率的贡献与中程有序(MRO)的关系。研究了三种不同的非晶态结构，其尺寸相同，为3.28 nm。在这三个结构中，两个结构是用实验观察到的MRO构建的[M.M.J.Treacy和K.B.Borisenko，Science 335,950(2012)]，另一个结构来自连续随机网络(CRN)，它没有MRO，因此代表随机的非晶态结构[G.Barkema和N.Mousseau，Phys.修订本B 62,4985(2000)]。利用模拟的涨落电子显微镜和二面角分布，我们证实了前两种结构在10-20A的长度范围内含有MRO，而CRN结构没有。利用分子动力学模拟数据的动态结构因子计算和简正波分解比较了传播子在MRO和CRN结构中的输运，发现在MRO结构中传播子的寿命比在CRN结构中要长得多。MRO结构中的传播热导率估计比CRN结构中的传播热导率大50%。由AIP出版公司授权出版。
We discuss the dependence of the propagon contribution to thermal conductivity on the medium range order (MRO) in amorphous silicon. Three different amorphous structures with the same size of 3.28 nm were studied. Among these three structures, two structures were constructed with experimentally observed MRO [M. M. J. Treacy and K. B. Borisenko, Science 335, 950 (2012)], and the other structure is from continuous random network (CRN), which lacks MRO and thus represents a randomized amorphous structure [G. Barkema and N. Mousseau, Phys. Rev. B 62, 4985 (2000)]. Using the simulated fluctuation electron microscopy and dihedral angle distribution, we confirm that the first two structures contain MRO in the length scale of 10-20 A while the CRN structure does not. The transport of propagons in the MRO and CRN structures is compared using the dynamic structural factor calculation and normal mode decomposition of the molecular dynamics simulation data, showing noticeably longer lifetime of propagons in MRO structures than in the CRN structure. The propagon thermal conductivity in MRO structures is estimated to be 50% larger than that in the CRN structure. Published under license by AIP Publishing.