An interlayer/intralayer coupling mechanism for the thermal characteristics of polycrystalline few-layer graphene

AR Wei and YF Li and WJ Ren and WJ Ye, APPLIED PHYSICS LETTERS, 114, 021902 (2019).

DOI: 10.1063/1.5064709

In this paper, the dependence of thermal conductivities of polycrystalline few-layer graphene (PFG) on the layer number and in- plane strain is systematically studied using the reverse non-equilibrium molecular dynamics method. The thermal conductivities are shown to decrease with the increased layer number, but the dependency on the layer number is anomalously less than what has been observed in single- crystalline few-layer graphene. Through a detailed analysis of the in- plane and out-of-plane phonon density of states, it is found that such a weak dependence can be explained by an interlayer/intralayer coupling mechanism, which is sensitive to the presence of grain boundaries. It is also found that this coupling mechanism can also be greatly influenced by in-plane tension, which indicates that thermal conductivities of PFG can be manipulated using in-plane tensile strains in addition to grain boundaries. The present study provides fundamental understanding and valuable guidelines for the design of graphene based flexible devices for efficient thermal management. Published under license by AIP Publishing.

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