Tunable Interfacial Thermal Conductance in Graphene/Germanene van der Waals Heterostructure using an Optimized Interlayer Potential

TL;DR

This study develops an optimized interlayer potential for graphene/germanene heterostructures to accurately model and tune interfacial thermal conductance via external strain, revealing significant control over heat transfer properties.

Contribution

The paper introduces a new pairwise interlayer potential based on ab-initio data, enabling precise simulation of thermal transport and its tunability in graphene/germanene heterostructures.

Findings

Interfacial thermal conductance can be increased by ~36% with compressive strain.

Tensile strain reduces conductance to about 70% of the unstrained value.

Temperature and interaction strength positively correlate with thermal conductance.

Abstract

Accurately modeling interfacial thermal transport in van der Waals heterostructures is challenging due to the limited availability of interlayer interaction potentials. We develop a pairwise interlayer potential for graphene/germanene van der Waals heterostructure using the binding energy obtained from ab-initio density functional theory calculations and use it to calculate the interfacial thermal conductivity. Our calculations reveal that the interfacial thermal conductivity shows superior tunability with external strain. The phonon density of states calculations show a blueshift in the phonon spectra with an applied compressive strain in the direction of heat flow, increasing the interfacial thermal conductance to $\sim$136% of the unstrained value. In contrast, a tensile strain is found to cause an opposite effect, reducing the conductance to $\sim$70% of the unstrained value. Moreover, due to increased availability of phonons for heat transfer, both temperature and interaction strength are found to correlate positively with the interfacial thermal conductance for both directions of heat flow.