半导体合金中的超扩散热传导-- II。用于实验分析的截断Lévy形式
Superdiffusive heat conduction in semiconductor alloys -- II. Truncated Lévy formalism for experimental analysis
摘要：
几乎所有的准弹道热流的实验观测解释与修改的导热系数傅立叶理论。然而，详细的玻尔兹曼输运方程（BTE）分析表明，半导体合金中热能的准弹道运动不再是布朗运动，而是表现出具有分形维数$α< 2$的Lévy动力学。在这里，我们提出了一个框架，使完整的3D实验分析保留所有基本物理的准弹道BTE动力学现象。一个只有两个拟合参数的随机过程描述了从长度和时间尺度都很短的纯Lévy超扩散到规则傅立叶扩散的过渡。该模型提供了准确的适合在整个调制频率范围内的时域热反射原始实验数据，而不需要任何“有效”的热参数，没有任何先验知识的微观声子散射机制。InGaAs和SiGe的识别$α$值在百分之几内匹配从头计算BTE预测。我们的结果提供了实验证据的分形Lévy热传导在半导体合金。该形式主义还表明，材料内部的瞬态温度与傅立叶理论显著不同，可以改善纳米级器件和材料界面的热特性。
英文摘要：
Nearly all experimental observations of quasi-ballistic heat flow are interpreted using Fourier theory with modified thermal conductivity. Detailed Boltzmann transport equation (BTE) analysis, however, reveals that the quasi-ballistic motion of thermal energy in semiconductor alloys is no longer Brownian but instead exhibits Lévy dynamics with fractal dimension $α< 2$. Here, we present a framework that enables full 3D experimental analysis by retaining all essential physics of the quasi-ballistic BTE dynamics phenomenologically. A stochastic process with just two fitting parameters describes the transition from pure Lévy superdiffusion as short length and time scales to regular Fourier diffusion. The model provides accurate fits to time domain thermoreflectance raw experimental data over the full modulation frequency range without requiring any `effective' thermal parameters and without any a priori knowledge of microscopic phonon scattering mechanisms. Identified $α$ values for InGaAs and SiGe match ab initio BTE predictions within a few percent. Our results provide experimental evidence of fractal Lévy heat conduction in semiconductor alloys. The formalism additionally indicates that the transient temperature inside the material differs significantly from Fourier theory and can lead to improved thermal characterization of nanoscale devices and material interfaces.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
