A fundamentally new approach of manipulating thermal properties is utilizing the wave nature of phonons, which can be realized by introducing secondary artificial periodicity in nanostructures. In this paper, we have studied the heat transport in silicene nanomesh (SNM, a silicene sheet with periodically arranged nanopores), using first-principles calculations and molecular dynamics simulations. The results show the thermal conductivity of SNM is obviously lower than that of silicene. Combining with the analysis of wave and particle characteristics of phonons, we reveal the main reasons responsible for the reduction in thermal conductivity of SNM. The coherent Bragg scattering from the secondary artificial periodicity leads to the reduction in phonon group velocities of LA and optical phonons. Different from the graphene nanomesh reported previously, multiple phonon bandgaps in the optical phonon spectrum of SNM are found for the first time. Moreover, it is noticed that, phonons are scattered not only at the hole boundaries, but also at the interface between the surface and interfacial regions in SNMs. In particular, the out-of-plane vibrations are easier to be scattered at the interface than the in-plane vibrations. This study uncovers the coherent and incoherent phonon transport in SNMs, which would deepen our understanding on heat conduction and shed light on the development of Si-based nanoelectronic devices.

操纵热性质的一种根本上新的方法是利用声子的波特性，这可以通过在纳米结构中引入二次人工周期性来实现。在本文中，我们使用第一性原理计算和分子动力学模拟研究了硅纳米网（SNM，具有周期性排列的纳米孔的硅片）中的热传递。结果表明，SNM的导热系数明显低于硅。结合声子的波和粒子特性分析，我们揭示了造成SNM导热系数降低的主要原因。来自次要人工周期的相干布拉格散射导致LA和光学声子的声子基团速度降低。与先前报道的石墨烯纳米网不同，首次发现了SNM光学声子谱中的多个声子带隙。而且，注意到，声子不仅在孔边界处散射，而且在SNM中的表面和界面区域之间的界面处也散射。特别地，平面外振动比平面内振动更容易在界面处分散。这项研究揭示了SNM中声子的相干和非相干传输，这将加深我们对热传导的理解，并为Si基纳米电子器件的发展提供启示。而且也位于SNM中表面和界面区域之间的界面处。特别地，平面外振动比平面内振动更容易在界面处分散。这项研究揭示了SNM中声子的相干和非相干传输，这将加深我们对热传导的理解，并为Si基纳米电子器件的发展提供启示。而且也位于SNM中表面和界面区域之间的界面处。特别地，平面外振动比平面内振动更容易在界面处分散。这项研究揭示了SNM中声子的相干和非相干传输，这将加深我们对热传导的理解，并为Si基纳米电子器件的发展提供启示。