论文标题
石墨烯晶界处的结构特异性，模式分辨的声子相干性和镜面性
Structure-specific, mode-resolved phonon coherence and specularity at graphene grain boundaries
论文作者
论文摘要
尽管它们对于理解薄膜和多晶固体中的声子传输现象的重要性，但对声子镜面性和相干性的边界粗糙度散射的影响却很少了解，因为没有一般方法可以预测它们对声子动量，频率，频率，分支和边界形态的依赖性。使用最近配制的原子S-Matrix方法，我们开发了一个边界粗糙度散射理论，以确定来自散射幅度的模式分辨的声子相干性和镜面参数。为了说明该理论，我们将其应用于来自原子结构预测的逼真的非对称石墨烯晶界（GB）模型中的声子散射。该方法通过将其预测与基于晶格动力学计算的频率分辨结果进行比较来验证。我们证明，不连贯的散射几乎是完全扩散的。我们表明，尽管对于长波长的弯曲声音声子显着降低了一致性和镜面，但在石墨烯GB上的声子散射并非散射。我们的方法可以推广到其他原子边界模型。
In spite of their importance for understanding phonon transport phenomena in thin films and polycrystalline solids, the effects of boundary roughness scattering on phonon specularity and coherence are poorly understood because there is no general method for predicting their dependence on phonon momentum, frequency, branch and boundary morphology. Using the recently formulated atomistic S-matrix method, we develop a theory of boundary roughness scattering to determine the mode-resolved phonon coherence and specularity parameters from the scattering amplitudes. To illustrate the theory, we apply it to phonon scattering in realistic nonsymmetric graphene grain boundary (GB) models derived from atomic structure predictions. The method is validated by comparing its predictions with frequency-resolved results from lattice dynamics-based calculations. We prove that incoherent scattering is almost perfectly diffusive. We show that phonon scattering at the graphene GB is not diffuse although coherence and specularity are significantly reduced for long-wavelength flexural acoustic phonons. Our approach can be generalized to other atomistic boundary models.
