Significant Reduction of Graphene Thermal Conductivity by Phononic Crystal Structure

TL;DR

This study demonstrates that introducing phononic crystal structures into graphene significantly reduces its thermal conductivity, which can be precisely tuned by adjusting porosity and period length, offering a new method for thermal management.

Contribution

The paper provides molecular dynamics simulation evidence that graphene phononic crystals drastically lower thermal conductivity and offers a way to control it via structural parameters.

Findings

Thermal conductivity of GPnCs is much lower than pristine graphene.

Porosity and period length effectively tune thermal conductivity.

Higher porosity leads to increased phonon localization.

Abstract

We studied the thermal conductivity of graphene phononic crystal (GPnC), also named as graphene nanomesh, by molecular dynamics simulations. The dependences of thermal conductivity of GPnCs on both length and temperature are investigated. It is found that the thermal conductivity of GPnCs is significantly lower than that of graphene and can be efficiently tuned by changing the porosity and period length. For example, the ratio of thermal conductivity of GPnC to thermal conductivity of graphene can be changed from 0.1 to 0.01 when the porosity is changed from about 21% to 65%. The phonon participation ratio spectra reveal that more phonon modes are localized in GPnCs with larger porosity. Our results suggest that creating GPnCs is a valuable method to efficiently manipulate the thermal conductivity of graphene.