论文标题
热电流的反相关效应导致纳米多孔SI导热率降低
Heat current anticorrelation effects leading to thermal conductivity reduction in nanoporous Si
论文作者
论文摘要
盛行的纳米结构策略专注于增加声子散射，并减少声子在整个频谱中的平均无路径。例如，在纳米多孔Si材料中，边界散射会大大降低热导率。在这项工作中，我们确定了异常的反相关的镜子散射效应，该效果可能导致特定纳米多孔几何形状的导热率最高〜80％的额外降低。我们进一步发现证据表明，这种作用起源于颈部狭窄的大毛孔之间的热量捕获。当热量被困在孔之间时，声子经历了多种镜面反射，以使其对导热率的贡献部分被撤销。我们发现这种作用是在低温下的波形依赖性的。我们使用大规模的分子动力学模拟，波数据包分析以及分析模型来说明抗相关效应，评估其对热导率的影响，并详细介绍如何控制其以操纵纳米多孔材料中的声子传输。
Prevailing nanostructuring strategies focus on increasing phonon scattering and reducing the mean-free-path of phonons across the spectrum. In nanoporous Si materials, for example, boundary scattering reduces thermal conductivity drastically. In this work, we identify an unusual anticorrelated specular phonon scattering effect which can result in additional reductions in thermal conductivity of up to ~ 80% for specific nanoporous geometries. We further find evidence that this effect has its origin in heat trapping between large pores with narrow necks. As the heat becomes trapped between the pores, phonons undergo multiple specular reflections such that their contribution to the thermal conductivity is partly undone. We find this effect to be wave-vector dependent at low temperatures. We use large-scale molecular dynamics simulations, wave packet analysis, as well as an analytical model to illustrate the anticorrelation effect, evaluate its impact on thermal conductivity, and detail how it can be controlled to manipulate phonon transport in nanoporous materials.
