Abstract Interfacial phonon-mediated heat transport plays a key role in nanoscale materials and devices. We propose a model based on elastic wave theory, that considers the mode conversion of acoustic waves transmitted across an interface and combines isotropic dispersion relations to describe the interfacial phonon thermal transfer process and estimate the thermal boundary conductance (TBC). In this model, we calculate the amplitude ratios of all reflected and transmitted acoustic waves using the frequency-dependent interfacial displacement and stress components of the continuity equation; we then determine the energy transmission coefficient of the three modes of incident waves. Consequently, our model can produce the complete angular and frequency spectra of the phonon transmission coefficients for the three acoustic modes. These results show that the specular scattering dominates the transmission of low-frequency phonons at interfaces (e.g., the transmission coefficients of the Al–Si interface are close to 1 below 4 THz, and due to different elastic properties, the phonons at frequencies below 5 THz dominate the heat transfer for Al–diamond interfaces). In addition, the TBC numerical results by our model for Al–Si and Al–diamond interfaces are consistent with those found in previous experimental works. Compared with existing theoretical models, better prediction values were obtained at temperatures higher than 100 K, which verified the model’s feasibility for phonon transmission coefficients and TBC prediction. Finally, we quantitatively analyze the differences between various theoretical models by considering the mode conversion of interfacial acoustic waves, models using acoustic mismatch simplifications, and the importance of phonon dispersion relations for TBC analysis at high temperatures.

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基于弹性波理论的热边界电导解析模型

摘要 界面声子介导的热传输在纳米材料和器件中起着关键作用。我们提出了一个基于弹性波理论的模型，该模型考虑了通过界面传输的声波的模式转换，并结合各向同性色散关系来描述界面声子热传递过程并估计热边界电导 (TBC)。在该模型中，我们使用连续性方程的频率相关界面位移和应力分量来计算所有反射和透射声波的振幅比；然后我们确定三种入射波模式的能量传输系数。因此，我们的模型可以产生三种声模式的声子传输系数的完整角度和频谱。这些结果表明镜面散射主导了界面处低频声子的传输（例如，Al-Si 界面的传输系数在 4 THz 以下接近 1，并且由于不同的弹性特性，频率低于 5太赫兹主导了铝-金刚石界面的传热）。此外，我们的模型对 Al-Si 和 Al-金刚石界面的 TBC 数值结果与先前实验工作中发现的结果一致。与现有理论模型相比，在高于100 K的温度下获得了更好的预测值，验证了该模型对声子传输系数和TBC预测的可行性。最后，我们通过考虑界面声波的模式转换，定量分析了各种理论模型之间的差异，