Thermal resistance from non-equilibrium phonons at Si–Ge interface
Thermal resistance from non-equilibrium phonons at Si–Ge interface
复制标题
Si–Ge 界面非平衡声子的热阻
DOI：
10.1016/j.mtphys.2023.101063
复制
发表时间：
2023
影响因子：
11.5
通讯作者：
Lee, Sangyeop
中科院分区：
文献类型：
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作者：
Li, Xun;Han, Jinchen;Lee, Sangyeop
随着纳米结构器件的普及，界面在热传输现象中往往起着重要的作用。然而，界面热输运仍然知之甚少，由于复杂的物理横跨从原子尺度到微米尺度的大范围的长度尺度。以往对界面热阻的研究主要集中在原子尺度下的界面-声子散射，而忽略了微观尺度下声子-界面和声子-声子散射的复杂相互作用。在这里，我们使用Peierls-Boltzmann输运方程表明，从声子-声子散射的非平衡声子附近的Si-Ge界面的阻力是远远大于直接引起的界面散射。我们报告说，根据玻尔兹曼H定理，声子分布的非平衡会导致三声子散射产生显着的熵产生和热阻。用声子色散、态密度和群速度的失配解释了Ge中非平衡声子的物理起源，为估算非平衡效应对界面热阻的影响提供了一般指导。我们的研究弥合了原子尺度和研究较少的微观现象之间的差距，提供了全面的了解整体界面热输运和声子-声子散射的重要作用。
As nanostructured devices become prevalent, interfaces often play an important role in thermal transport phenomena. However, interfacial thermal transport remains poorly understood due to complex physics across a wide range of length scales from atomistic to microscale. Past studies on interfacial thermal resistance have focused on interface-phonon scattering at the atomistic scale but overlooked the complex interplay of phonon-interface and phonon-phonon scattering at microscale. Here, we use the Peierls-Boltzmann transport equation to show that the resistance from the phonon-phonon scattering of non-equilibrium phonons near a Si–Ge interface is much larger than that directly caused by the interface scattering. We report that non-equilibrium in phonon distribution leads to significant entropy generation and thermal resistance upon three-phonon scattering by the Boltzmann's H-theorem. The physical origin of non-equilibrium phonons in Ge is explained with the mismatches of phonon dispersion, density-of-states, and group velocity, which serve as general guidance for estimating the non-equilibrium effect on interfacial thermal resistance. Our study bridges a gap between atomistic scale and less studied microscale phenomena, providing comprehensive understanding of overall interfacial thermal transport and the significant role of phonon-phonon scattering.