Specular transmission and diffuse reflection in phonon scattering at grain boundary

Abstract

It is widely assumed in the literature that the specularity parameters for phonon transmission (forward scattering) and reflection (backward scattering) at a boundary are identical, i.e., the statistical distributions of the transition probabilities between an incident phonon and the range of outgoing phonon modes are the same for both transmission and reflection. However, it is hypothesized by Li and McGaughey that separate specularity parameters are needed to describe the behavior of transmitted and reflected phonons in superlattices and polycrystalline materials correctly. We test this hypothesis by analyzing the mode-resolved specularity parameters computed separately for transmission and reflection processes at a graphene grain boundary. Our results show that backward scattering is considerably more diffuse than forward scattering at most frequencies and polarizations, providing strong evidence for Li and McGaughey's hypothesis, and shed new light on how surfaces and interfaces modify phonon transport within and between domains in nanostructured materials.

7 pages, 5 figures in main text (8 pages, 4 figures in supplemental material)

References in corpus (7)

• High-pressure phases of silane
• Importance of frequency-dependent grain boundary scattering in nanocrystalline silicon and silicon-germanium thermoelectrics
• Predicting interface structures: From SrTiO${}_3$ to graphene
• Boundary scattering of phonons: specularity of a randomly rough surface in the small perturbation limit
• Scattering of flexural acoustic phonons at grain boundaries in graphene
• Structure-specific, mode-resolved phonon coherence and specularity at graphene grain boundaries
• Complementary local-global approach for phonon mode connectivities

Cited by in corpus (4)

• Evaluation of diffuse mismatch model for phonon scattering at disordered interfaces
• The Atomistic Green's Function method for acoustic and elastic wave-scattering problems
• Effect of boundary roughness on the attenuation of specular phonon reflection in graphene
• Control of wave scattering for robust coherent transmission in a disordered medium