Thermal Conductivity of Graphene Wrinkles: A Molecular Dynamics Simulation
L Cui and XZ Du and GS Wei and YH Feng, JOURNAL OF PHYSICAL CHEMISTRY C, 120, 23807-23812 (2016).
Based on the nonequilibrium molecular dynamics simulations, the heat conduction in a novel deformation of graphene, named graphene wrinkle (GW), is investigated. Distinct from pristine graphene, the GW exhibits a relatively low thermal conductivity. We observe that the low thermal conductivity stems from the strong phonon localizations, which are concentrated on the joint regions between crests and troughs of wrinkles. The suppression in GW thermal conductivity could be further attributed to the enhanced phonon scatterings, as evidenced by the vibrational density of states (VDOS) attenuation in the low frequency region, the G-band redshift of VDOS due to the flattened phonon dispersion curves (low phonon group velocities), and the decreased phonon lifetime. In addition, we find that the thermal conductivity of GW is almost insensitive to temperature in the range between 200 and 600 K. It is induced by the significant contribution of low frequency phonon modes, which are more influential in the direction perpendicular to the wrinkle texture. This study provides physical insight into the mechanisms of thermal transport in GWs and offers design guidelines for applications of GW related devices.
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