Abstract Coherent thermal transport has recently become a subject of considerable interest, but whether some intriguing phenomena of phonon coherence (including Brillouin zone folding, phonon localization, and phonon confinement) occur in certain nanostructures remains unclear. We have investigated the thermal transport in graphene nanomesh using molecular dynamics simulations together with first-principles calculations. It is found that the thermal conductivity of nanomesh is significantly reduced compared with graphene, mainly due to the bandgaps, flattened phonon dispersions and reduced phonon group velocities induced by Brillouin zone folding. Meanwhile, the significant decrease in thermal conductivity is induced by phonon localization. Phonon confinement caused by reflecting the optical phonon modes back into the C-H part further leads to the reduction of thermal conductivity. We highlight the coherent mechanism for lowering thermal conductivity, which is useful for manipulating heat conduction for thermoelectrics and thermal insulation applications.

中文翻译：

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石墨烯纳米网中的热传输：揭示布里渊区折叠、声子定位和声子约束的作用

摘要 相干热传输最近成为一个相当有趣的主题，但某些纳米结构中是否发生了一些有趣的声子相干现象（包括布里渊区折叠、声子定位和声子限制）仍不清楚。我们使用分子动力学模拟和第一性原理计算研究了石墨烯纳米网中的热传输。发现与石墨烯相比，纳米网的热导率显着降低，主要是由于带隙、平坦的声子色散和布里渊区折叠引起的声子群速度降低。同时，声子定位引起热导率的显着降低。由将光学声子模式反射回 CH 部分引起的声子限制进一步导致热导率的降低。我们强调了降低热导率的连贯机制，这对于操纵热电和绝热应用的热传导非常有用。