Thermal Transport in Twisted Bilayer Graphene: An Equilibrium Molecular Dynamics Study

TL;DR

This study investigates how twisting bilayer graphene affects its thermal properties, revealing that twist angle influences thermal conductivity and that quantum corrections are necessary for accurate low-temperature predictions.

Contribution

It provides a comprehensive analysis of thermal conductivity, phonon density of states, and specific heat capacity of twisted bilayer graphene across various angles and temperatures using molecular dynamics.

Findings

Thermal conductivity decreases with twisting, with a maximum at 3.89°

Quantum corrections increase accuracy of low-temperature thermal conductivity

Twist angle significantly impacts thermal transport properties

Abstract

Twisted bilayer graphene (tBLG) is two graphene layers placed on top of each other with a twist angle, making it has tunable thermal properties. In this paper, we report an analysis of thermal conductivity ($\kappa$), phonon density of states, and specific heat capacity of tBLG with various twist angles over a range of temperatures using equilibrium molecular dynamics simulations based on the Green-Kubo method. Simulation shows that stacking and twisting graphene layers lead to a decrease in the thermal conductivity, with the highest $\kappa$ at around room temperature owned by the tBLG with a twist angle of 3.89$^{\circ}$ followed by 16.43$^{\circ}$ and 4.41$^{\circ}$. We also perform quantum correction to the simulation results to show the process of increasing thermal conductivity at low temperatures.