论文标题
来自第一原理的二维材料中的声子传输
Phonon Transport in Patterned Two-Dimensional Materials from First Principles
论文作者
论文摘要
声子大小影响纳米材料中的弹道传输，挑战了傅立叶定律。 Peierls-Boltzmann传输方程（BTE）捕获了非造成热传输，该方程通常在放松时间近似（RTA）下解决，该近似值（RTA）假设对角散射算子。尽管RTA对于许多相关材料（例如硅）中的许多相关材料是准确的，但在大多数二维（2D）系统中，它低估了热传输，臭名昭著的石墨烯。在这里，我们提出了一种基于完整碰撞矩阵的BTE的形式主义，用于计算任意图案的2D材料的有效导热率。我们将方法应用于多孔石墨烯，并在具有微米级的特征大小的构型中找到强大的热抑制作用；该结果植根于石墨烯中大型的广义声子MFP，通过相对粗糙的图案来证实强烈的热传输可调性的可能性。最后，我们提出了一种有希望的材料构型，导热率低。我们的方法启用了用于热电和热路由应用的2D材料的无参数设计。
Phonon size effects induce ballistic transport in nanomaterials, challenging Fourier's law. Nondiffusive heat transport is captured by the Peierls-Boltzmann transport equation (BTE), commonly solved under the relaxation time approximation (RTA), which assumes diagonal scattering operator. Although the RTA is accurate for many relevant materials over a wide range of temperatures, such as silicon, it underpredicts thermal transport in most two-dimensional (2D) systems, notoriously graphene. Here we present a formalism, based on the BTE with the full collision matrix, for computing the effective thermal conductivity of arbitrarily patterned 2D materials. We apply our approach to porous graphene and find strong heat transport suppression in configurations with feature sizes of the order of micrometers; this result, which is rooted in the large generalized phonon MFPs in graphene, corroborates the possibility of strong thermal transport tunability by relatively coarse patterning. Lastly, we present a promising material configuration with low thermal conductivity. Our method enables the parameter-free design of 2D materials for thermoelectric and thermal routing applications.
