Analytical Models of Phonon-Point-Defect Scattering
Analytical Models of Phonon-Point-Defect Scattering
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DOI：
10.1103/physrevapplied.13.034011
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发表时间：
2020-03-04
影响因子：
4.6
通讯作者：
Snyder, G. Jeffrey
中科院分区：
文献类型：
--
作者：
Gurunathan, Ramya;Hanus, Riley;Snyder, G. Jeffrey
点缺陷广泛存在于工程材料中，并且已知点缺陷散射振动模式，导致热导率降低。点缺陷散射的Klemens描述是这种效应的最多产的分析模型。这项工作回顾了基本的物理模型，并将其预测与同位素和合金散射的第一性原理结果进行了比较，证明了该模型是材料设计的一个有用的度量。建议多原子晶格的散射参数（伽马）的治疗，并与文献中提出的其他治疗方法相比，有时被滥用，产生不完整的结论系统的散射机制。此外，我们证明了降低的灵敏度的模型，以充分的声子色散，并讨论其起源。最后，一个简化的处理与空位和间隙缺陷的合金系统中的散射证明适当地描述这些非化学计量缺陷的强散射强度。
Point defects exist widely in engineering materials and are known to scatter vibrational modes, resulting in reduction in thermal conductivity. The Klemens description of point-defect scattering is the most-prolific analytical model for this effect. This work reviews the essential physics of the model and compares its predictions with first-principles results for isotope and alloy scattering, demonstrating the model to be a useful metric of material design. A treatment of the scattering parameter (Gamma) for a multiatomic lattice is recommended and compared with other treatments presented in the literature, which have been at times misused to yield incomplete conclusions about the system's scattering mechanisms. Additionally, we demonstrate a reduced sensitivity of the model to the full phonon dispersion and discuss its origin. Finally, a simplified treatment of scattering in alloy systems with vacancies and interstitial defects is demonstrated to suitably describe the potent scattering strength of these off-stoichiometric defects.