Anisotropic nature of thermal conductivity in graphene spirals revealed by molecular dynamics simulations

Spiral nanostructures with many potential applications in next-generation high-tech industries can show outstanding mechanical, electrical and thermal properties thanks to their special topologies. In this study, we report a detailed analysis of heat transport in graphene spiral nanostructures. The non-equilibrium molecular dynamics simulation is used to investigate the thermal conductivity of the spirals in both axial (symmetric) and radial (asymmetric) directions for different geometries. The results reveal that with increasing widths of the graphene spirals, effective thermal conductivity (kA) in the axial direction and the thermal conductivity (k) in the radial direction increase. But with increasing the lengths of the graphene spirals (number of turns), only the axial thermal conductivity increases. Furthermore, the axial tensile strain and the addition of an extra layer to form a double-layer spiral structure have positive effects on increasing the thermal conductivity in the axial direction. Moreover, the results show that the thermal conductivity in radially inward and outward directions differ from each other arising from asymmetricity between the two radial directions where the heat flux prefers the inward direction. •Thermal conductivity of graphene spirals in axial direction.•Thermal conductivity and rectification in radial direction of graphene spirals.•Strain effects on the thermal conductivity of graphene spirals.