Tunable interfacial thermal conductance in graphene/germanene van der Waals heterostructure using an optimized interlayer potential

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 heterostructures 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 (ITC) to ∼136% of the unstrained value. In contrast, a tensile strain is found to cause an opposite effect, reducing the conductance to ∼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 ITC for both directions of heat flow.