Hunan Key Laboratory for Micro-Nano Energy Materials, Xiangtan University, Xiangtan 411105, Hunan, China.
Sci Rep. 2017 Apr 4;7:45986. doi: 10.1038/srep45986.
The phonon transport property is a foundation of understanding a material and predicting the potential application in mirco/nano devices. In this paper, the thermal transport property of borophene is investigated by combining first-principle calculations and phonon Boltzmann transport equation. At room temperature, the lattice thermal conductivity of borophene is found to be about 14.34 W/mK (error is about 3%), which is much smaller than that of graphene (about 3500 W/mK). The contributions from different phonon modes are qualified, and some phonon modes with high frequency abnormally play critical role on the thermal transport of borophene. This is quite different from the traditional understanding that thermal transport is usually largely contributed by the low frequency acoustic phonon modes for most of suspended 2D materials. Detailed analysis further reveals that the scattering between the out-of-plane flexural acoustic mode (FA) and other modes likes FA + FA/TA/LA/OP ↔ TA/LA/OP is the predominant phonon process channel. Finally the vibrational characteristic of some typical phonon modes and mean free path distribution of different phonon modes are also presented in this work. Our results shed light on the fundamental phonon transport properties of borophene, and foreshow the potential application for thermal management community.
声子输运性质是理解材料和预测微纳器件潜在应用的基础。本文通过第一性原理计算和声子玻尔兹曼输运方程结合，研究了硼烯的热输运性质。在室温下，硼烯的晶格热导率约为 14.34 W/mK（误差约为 3%），远小于石墨烯（约 3500 W/mK）。分析了不同声子模式的贡献，一些高频声子模式异常地对硼烯的热输运起着关键作用。这与传统的理解大相径庭，传统的理解是，对于大多数悬浮的二维材料，热输运通常主要由低频声学声子模式贡献。详细的分析进一步表明，面外挠曲声模（FA）与其他模式之间的散射（如 FA + FA/TA/LA/OP↔TA/LA/OP）是主要的声子散射过程。最后，本文还展示了一些典型声子模式的振动特性和声子模式的平均自由程分布。我们的研究结果阐明了硼烯的基本声子输运性质，并为热管理领域的潜在应用提供了参考。
