Tunable thermal rectification in silicon-functionalized graphene nanoribbons by molecular dynamics simulation

•Thermal rectification in graphene nanoribbons is investigated using NEMD.•Thermal rectification can be tuned by the Si/C ratio and silicon distribution.•Rectification factor is sensitive to temperature and phonon ballistic transport.

In this paper, we investigate thermal rectification in hybrid pristine and silicon-functionalized graphene nanoribbons (GNRs) using nonequilibrium molecular dynamics simulations. The heat flux is larger from the functionalized section to the pristine section than that in the opposite direction. It is found that thermal rectification can be tuned through the Si/C ratio and silicon distribution. A moderate Si/C ratio and patterned arrangement are preferable to obtain a higher rectification factor. The rectification factor is also sensitive to the temperature difference and the mean temperature. As the length of the system increases, the rectification factor decreases gradually due to the emerging of diffusive effect in nanoscale GNRs. Furthermore, we calculate the vibrational density of states to explain the underlying mechanism of thermal rectification.