Diffraction and near-zero transmission of flexural phonons at graphene grain boundaries

TL;DR

This study investigates how graphene grain boundaries influence flexural phonon transmission, revealing strong angle-dependent suppression and diffraction effects that impact thermal transport properties.

Contribution

It provides new insights into phonon diffraction and transmission suppression at graphene grain boundaries using molecular dynamics simulations.

Findings

Transmission is strongly suppressed near 35° incidence angle.

Grain boundaries act as diffraction gratings for phonons.

Flexural phonons are significantly affected by grain boundary structure.

Abstract

Graphene grain boundaries are known to affect phonon transport and thermal conductivity, suggesting that they may be used to engineer the phononic properties of graphene. Here, the effect of two buckled grain boundaries on long-wavelength flexural acoustic phonons has been investigated as a function of angle of incidence using molecular dynamics. The flexural acoustic mode has been chosen due to its importance to thermal transport. It is found that the transmission through the boundaries is strongly suppressed for incidence angles close to 35$^\circ$. Also, the grain boundaries are found to act as diffraction gratings for the phonons.