Thermal stability and morphological variation of carbon nanorings of different radii during the temperature elevating process: a molecular dynamics simulation study

We study the thermal stability and morphological variations of nanorings with different radii during the temperature elevation using the molecular dynamics (MD) simulation method. Five metastable nanorings were generated using the different initial C-C bond length of armchair carbon nanotubes. The stable structures of the two smallest nanorings have several kinked regions around the nanorings, with the deformations of the inner and outer walls occurring at the same temperature. For the largest three cases, the morphologies of nanorings from the top view display circular shapes at 0 K. For the nanoring with a radius of 146 (350 units), the thermal deformation process is very similar to the smallest two cases, but the temperature at which the thermal deformation begins is higher. For the nanoring with nanoring radii of 165 (400 units) and 185 (450 units), thermal deformation will take place at the inner wall of the nanoring, and then will induce deformation of the outer wall at a higher temperature. Variations of local structures at the kinked regions at different temperatures are also drawn.