Thermal rectification and interfacial thermal resistance in hybrid pillared-graphene and graphene: a molecular dynamics and continuum approach

Abstract

In this study, we investigate the thermal rectification and thermal resistance in the hybrid pillared-graphene and graphene (PGG) system. This is done through the classical molecular dynamics simulation (MD) and also with a continuum model. At first, the thermal conductivity of both pillared-graphene and graphene is calculated employing MD simulation and Fourier's low. Our results show that the thermal conductivity of the pillared-graphene is much smaller than the graphene by an order of magnitude. Next, by applying positive and negative temperature gradients along the longitudinal direction of PGG, the thermal rectification is examined. The MD results indicate that for the lengths in the range of 36 to 86 nm, the thermal rectification remains almost constant (~3-5%). We have also studied the phonon density of states (DOS) on both sides of the interface of PGG. The DOS curves show that there is phonon scattering at low frequencies (acoustic mode) that depends on the imposed temperature gradient direction in the system. Therefore, we can 2 introduce the PGG as a promising thermal rectifier at room temperature. Furthermore, in the following of this work, we also explore the temperature distribution over the PGG by using the continuum model. The results that obtained from the continuum model predict the MD results such as the temperature distribution in the upper half-layer and lower full-layer graphene, the temperature gap and also the thermal resistance at the interface.

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