论文标题
异质固体中原子局部局部成分依赖性界面声子
Atomically localized ingredient-dependent interface phonon in heterogeneous solids
论文作者
论文摘要
声子是非金属固体中的主要热载体。在组成异质材料中，据信热性能主要受质量障碍和应变波动引起的声子传输的约束，而组成波动引起的局部声子状态的影响通常被忽略。在这里，通过扫描透射电子显微镜电子能量损耗光谱和复杂的计算，我们确定了Alxga1-XN中成分依赖性界面声子模式的振动特性，并量化了它们对局部界面热电导率的各种贡献。我们证明，原子尺度的组成波动对振动热力学特性具有重大影响，高度影响了界面声子模式的模式比和振动幅度，并随后重新分布了其对ITC的模态贡献。我们的工作为理解纳米级不均匀性的本地声子与结合互动的理解提供了基本见解，这揭示了通过工程成分分布来优化热性能的新机会。
Phonons are the primary heat carriers in non-metallic solids. In compositionally heterogeneous materials, the thermal properties are believed to be mainly governed by the disrupted phonon transport due to mass disorder and strain fluctuations, while the effects of compositional fluctuation induced local phonon states are usually ignored. Here, by scanning transmission electron microscopy electron energy loss spectroscopy and sophisticated calculations, we identify the vibrational properties of ingredient-dependent interface phonon modes in AlxGa1-xN and quantify their various contributions to the local interface thermal conductance. We demonstrate that atomic-scale compositional fluctuation has significant influence on the vibrational thermodynamic properties, highly affecting the mode ratio and vibrational amplitude of interface phonon modes and subsequently redistributing their modal contribution to the ITC. Our work provides fundamental insights into understanding of local phonon-boundary interactions in nanoscale inhomogeneities, which reveal new opportunities for optimization of thermal properties via engineering ingredient distribution.
