Key Laboratory of Condition Monitoring and Control for Power Plant Equipment, Ministry of Education, North China Electric Power University, Changping, Beijing 102206, China.
Phys Chem Chem Phys. 2018 Oct 31;20(42):27169-27175. doi: 10.1039/c8cp03993c.
Silicene nanomesh (SNM), a silicene sheet with periodically arranged nanoholes, has gained increasing interest due to its unique geometry and novel properties. In this paper, we have conducted molecular dynamics simulations to study the phonon transport properties of SNMs. The results demonstrate that the thermal conductivity of SNM, which is shown to be much lower than that of silicene, is little affected by temperature but can be effectively tuned by varying the porosity. To elucidate the underlying mechanisms for decreased thermal conductivity, we have investigated both coherent and incoherent phonon transport in SNMs. It is found that the phonon backscattering at the nanopore edges leads to extra thermal resistances. Additionally, the introduction of nanopores induces phonon localization and consequently hinders phonon transport in SNMs. The phonons of SNM exhibit coherent resonant behavior, which is believed to reduce the phonon group velocities and thus leads to a further reduction in thermal conductivity of SNMs. Our findings could be useful in the design of thermal properties of silicene for applications in thermoelectrics, thermal insulation and thermal protection.
硅烯纳米网 (SNM) 是一种具有周期性纳米孔的硅烯薄片，由于其独特的几何形状和新颖的性质而引起了越来越多的关注。在本文中，我们进行了分子动力学模拟，以研究 SNM 的声子输运性质。结果表明，SNM 的热导率明显低于硅烯，其对温度的影响较小，但可以通过改变孔隙率来有效调节。为了阐明热导率降低的潜在机制，我们研究了 SNM 中的相干和非相干声子输运。结果发现，纳米孔边缘的声子背散射导致了额外的热阻。此外，纳米孔的引入诱导了声子局域化，从而阻碍了 SNM 中的声子输运。SNM 的声子表现出相干共振行为，这被认为会降低声子群速度，从而导致 SNM 的热导率进一步降低。我们的研究结果对于设计用于热电、隔热和热防护的硅烯的热性能可能是有用的。
