Radial Quasiballistic Transport in Time-Domain Thermoreflectance Studied Using Monte Carlo Simulations
Radial Quasiballistic Transport in Time-Domain Thermoreflectance Studied Using Monte Carlo Simulations
复制标题
使用蒙特卡罗模拟研究时域热反射中的径向准弹道输运
DOI：
10.1063/1.4870811
复制
发表时间：
2014
影响因子：
4
通讯作者：
A. Minnich
中科院分区：
文献类型：
--
作者：
D. Ding;X. Chen;A. Minnich
最近，利用时域热反射（TDTR）在低温下观察到了硅的热导率与泵浦光束尺寸的关系。这些观测结果归因于准弹道声子输运，但对测量结果的解释是半经验的。在这里，我们提出了一个数值研究的热传导发生在全三维几何的TDTR实验，包括接口，使用玻尔兹曼输运方程。与傅里叶定律相比，我们确定了描述热通量抑制的径向抑制函数，该函数是由于准弹道输运而发生的，并与实验数据表现出良好的一致性。我们还讨论了未解决的差异，是未来研究的重要课题。
Recently, a pump beam size dependence of thermal conductivity was observed in Si at cryogenic temperatures using time-domain thermal reflectance (TDTR). These observations were attributed to quasiballistic phonon transport, but the interpretation of the measurements has been semi-empirical. Here, we present a numerical study of the heat conduction that occurs in the full 3D geometry of a TDTR experiment, including an interface, using the Boltzmann transport equation. We identify the radial suppression function that describes the suppression in heat flux, compared to Fourier's law, that occurs due to quasiballistic transport and demonstrate good agreement with experimental data. We also discuss unresolved discrepancies that are important topics for future study.