Kapitza thermal resistance across individual grain boundaries in graphene

TL;DR

This study investigates heat transfer across individual grain boundaries in graphene, revealing how tilt angle and defect density influence Kapitza resistance, with quantum corrections aligning classical MD results with quantum calculations.

Contribution

It introduces a comprehensive MD simulation approach combined with quantum corrections to accurately quantify Kapitza resistance in graphene grain boundaries.

Findings

Kapitza resistance varies with tilt angle and defect density.

Quantum effects significantly affect resistance measurements.

Quantum-corrected MD results agree with Landauer-Büttiker calculations.

Abstract

We study heat transport across individual grain boundaries in suspended monolayer graphene using extensive classical molecular dynamics (MD) simulations. We construct bicrystalline graphene samples containing grain boundaries with symmetric tilt angles using the two-dimensional phase field crystal method and then relax the samples with MD. The corresponding Kapitza resistances are then computed using nonequilibrium MD simulations. We find that the Kapitza resistance depends strongly on the tilt angle and shows a clear correlation with the average density of defects in a given grain boundary, but is not strongly correlated with the grain boundary line tension. We also show that quantum effects are significant in quantitative determination of the Kapitza resistance by applying the mode-by-mode quantum correction to the classical MD data. The corrected data are in good agreement with quantum mechanical Landauer-B\"utticker calculations.