Defect-Engineered Thermal Transport in Wrinkled Graphene: A Comprehensive Molecular Dynamics Study

The out-of-plane morphology of graphene can be easily engineered with topological defects so as to adjust its thermal and mechanical properties. Herein, the heat transport behaviors of graphene with topological defect-induced wrinkles are systematically investigated by using nonequilibrium molecular dynamics simulations. Distinct from pristine graphene, the wrinkled graphene exhibits much lower thermal conductivity. By analyzing the vibrational density of states and atomic heat flux distribution, it is found that the phonon scattering enhancement caused by topological defects is the major mechanism of the thermal conductivity decrease, especially for the wrinkled graphene with a large aspect ratio of wrinkles. Besides, the thermal conductivity of wrinkled graphene is insensitive to sample size due to the extremely low phonon mean free path (MFP) caused by the topological defects. Furthermore, the thermal conductivity of wrinkled graphene is also insensitive to temperature due to the low MFP as well as the large contribution of low-frequency phonons in thermal transport. The present study offers a physical insight into the mechanisms of topological defects on thermal transport of graphene, which may offer topological optimization strategies for engineering the thermal conductivity of graphene with defects.