Abstract
We study the interfacial thermal conductance of grain boundaries (GBs) between monolayer graphene and hexagonal boron nitride (h-BN) sheets using a combined atomistic approach. First, realistic samples containing graphene/h-BN GBs with different tilt angles are generated using the phase-field crystal model developed recently [P. Hirvonen et al., Phys. Rev. B 100, 165412 (2019)] that captures slow diffusive relaxation inaccessible to molecular dynamics (MD) simulations. Then, large-scale MD simulations using the efficient GPUMD package are performed to assess heat transport and rectification properties across the GBs. We find that lattice mismatch between the graphene and h-BN sheets plays a less important role in determining the interfacial thermal conductance as compared to the tilt angle. In addition, we find no significant thermal rectification effects for these GBs.
Highlights
After the discovery of atomically thin two-dimensional (2D) graphene and other low-dimensional materials, there is a major effort in constructing heterostructures made of them, either by stacking 2D materials vertically to form multi-layer heterostructures1 or by stitching them laterally to form a 2D sheet with in-plane junctions
We find that the lattice mismatch between the graphene and hexagonal boron nitride (h-BN) sheets does not play a crucial role in determining the interfacial thermal conductance and no significant thermal rectification can be found
These findings suggest that heat transport properties in lateral graphene/h-BN heterostructures are not very sensitive to the actual microstructures of the grain boundaries (GBs)
Summary
After the discovery of atomically thin two-dimensional (2D) graphene and other low-dimensional materials, there is a major effort in constructing heterostructures made of them, either by stacking 2D materials vertically to form multi-layer heterostructures or by stitching them laterally to form a 2D sheet with in-plane junctions. To gain a thorough microscopic understanding of the role of phonons in heat transport in lateral graphene/h-BN heterostructures, MD simulations are the tool of choice. After obtaining relaxed atomistic configurations for such systems, we use them as input to MD simulations and systematically study the heat transport properties across these graphene/h-BN GBs. We find that the lattice mismatch between the graphene and h-BN sheets does not play a crucial role in determining the interfacial thermal conductance and no significant thermal rectification can be found. We find that the lattice mismatch between the graphene and h-BN sheets does not play a crucial role in determining the interfacial thermal conductance and no significant thermal rectification can be found These findings suggest that heat transport properties in lateral graphene/h-BN heterostructures are not very sensitive to the actual microstructures of the GBs
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