Thermal transport in bismuth telluride quintuple layer: mode-resolved phonon properties and substrate effects.
Thermal transport in bismuth telluride quintuple layer: mode-resolved phonon properties and substrate effects.
复制标题
碲化铋五重层中的热传输：模式分辨声子特性和基底效应
DOI：
10.1038/srep27492
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发表时间：
2016-06-06
影响因子：
4.6
通讯作者：
Bao H
中科院分区：
文献类型：
--
作者：
Shao C;Bao H
碲化铋（Bi 2 Te 3）五重层（QL）的成功剥离引起了人们对这种强非谐准二维材料的极大研究兴趣。这种材料的热输运性质还没有得到很好的理解，特别是模式的属性，当它与基板耦合。在这项工作中，我们进行了分子动力学模拟和正常模式分析，研究模式分辨的热输运在独立和支持Bi 2 Te 3 QL。详细的模式方式的声子性质的计算和累积热导率相对于声子平均自由程（MFP）的构造。结果表明，60%的热输运是由与MFP大于20 nm的声子。与a-SiO2衬底耦合导致热导率降低约60%。通过改变界面耦合强度和衬底原子质量，我们还发现Bi_2Te_3QL中声子受界面势的散射更强，其输运过程受衬底动力学的影响较小。我们的研究提供了一个深入的了解Bi 2 Te 3 QL中的热传输，并有助于通过纳米结构进一步定制其热性能。
The successful exfoliation of atomically-thin bismuth telluride (Bi2Te3) quintuple layer (QL) attracts tremendous research interest in this strongly anharmonic quasi-two-dimensional material. The thermal transport properties of this material are not well understood, especially the mode-wise properties and when it is coupled with a substrate. In this work, we have performed molecular dynamics simulations and normal mode analysis to study the mode-resolved thermal transport in freestanding and supported Bi2Te3 QL. The detailed mode-wise phonon properties are calculated and the accumulated thermal conductivities with respect to phonon mean free path (MFP) are constructed. It is shown that 60% of the thermal transport is contributed by phonons with MFP longer than 20 nm. Coupling with a-SiO2 substrate leads to about 60% reduction of thermal conductivity. Through varying the interfacial coupling strength and the atomic mass of substrate, we also find that phonon in Bi2Te3 QL is more strongly scattered by interfacial potential and its transport process is less affected by the dynamics of substrate. Our study provides an in-depth understanding of heat transport in Bi2Te3 QL and is helpful in further tailoring its thermal property through nanostructuring.