Effect of Stone-Wales defects on the thermal conductivity of graphene

TL;DR

This paper investigates how Stone-Wales defects affect phonon scattering and thermal conductivity in graphene, revealing that defects significantly reduce thermal conductivity at low temperatures, with phonon-phonon scattering dominating at room temperature.

Contribution

It provides an explicit model for phonon-SW scattering and quantifies the impact of SW defects on the thermal conductivity of graphene nanoribbons.

Findings

SW defects decrease thermal conductivity at low temperatures

Phonon-phonon scattering dominates at room temperature

Vacancy defects have a greater impact than SW defects across temperatures

Abstract

The problem of phonon scattering by strain fields caused by Stone-Wales (SW) defects in graphene is studied in the framework of the deformation potential approach. An explicit form of the phonon mean free path due to phonon-SW scattering is obtained within the Born approximation. The mean free path demonstrates a specific $q$-dependence varying as $q^{-3}$ at low wavevectors and taking a constant value at large $q$. The thermal conductivity of graphene nanoribbons (GNRs) is calculated with the three-phonon umklapp, SW and rough edge scatterings taken into account. A pronounced decrease of the thermal conductivity due to SW defects is found at low temperatures whereas at room temperatures and above the phonon-phonon umklapp scattering becomes dominant. A comparison with the case of vacancy defects shows that they play more important role in the reduction of the thermal conductivity in GNRs over a wide temperature range.