A compact heat transfer model based on an enhanced Fourier law for analysis of frequency-domain thermoreflectance experiments
A compact heat transfer model based on an enhanced Fourier law for analysis of frequency-domain thermoreflectance experiments
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基于增强傅里叶定律的紧凑传热模型，用于分析频域热反射实验
DOI：
10.1063/1.4923310
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发表时间：
2015
影响因子：
4
通讯作者：
J. Bowers
中科院分区：
文献类型：
--
作者：
A. Ramu;J. Bowers
最近开发的增强型傅里叶定律应用于从频域热反射（FDTR）实验中提取材料热特性的问题。传热模型包括来自两个声子通道的贡献：一个是由平均自由程 (MFP) 小于阈值的声子组成的高热容扩散通道，另一个是由 MFP 高于该值的声子组成的低热容通道，这些声子在感兴趣的长度尺度上以准弹道方式行进。使用傅里叶定律处理扩散通道，而使用声子分布函数的二阶球谐展开来分析准弹道通道。最近对 FDTR 实验数据的分析表明，可以使用 FDTR 来推导 MFP 累积函数的大部分；然而，这里表明，使用我们的最小参数模型可以充分解释数据，从而突出了 FDTR 实验在探索大块物质的累积函数方面的重要局限性。
A recently developed enhanced Fourier law is applied to the problem of extracting thermal properties of materials from frequency-domain thermoreflectance (FDTR) experiments. The heat transfer model comprises contributions from two phonon channels: one a high-heat-capacity diffuse channel consisting of phonons of mean free path (MFP) less than a threshold value, and the other a low-heat-capacity channel consisting of phonons with MFP higher than this value that travel quasi-ballistically over length scales of interest. The diffuse channel is treated using the Fourier law, while the quasi-ballistic channel is analyzed using a second-order spherical harmonic expansion of the phonon distribution function. A recent analysis of FDTR experimental data suggested the use of FDTR in deriving large portions of the MFP accumulation function; however, it is shown here that the data can adequately be explained using our minimum-parameter model, thus highlighting an important limitation of FDTR experiments in exploring the accumulation function of bulk matter.