Heat-Induced Transformation of Nanodiamond into a Tube-Shaped Fullerene: A Molecular Dynamics Simulation

Heat-induced structural transformation in nanodiamond of diameter $\sim 1.4\mathrm{n}\mathrm{m}$ is investigated by tight-binding molecular dynamics simulations using the environment-dependent tight-binding carbon potential. The nanodiamond is found to transform into a tube-shaped fullerene via annealing. Three interesting mechanisms for promoting inner carbon atoms of the nanodiamond into the surface carbon atoms of the tubular structure are observed. The “flow-out” mechanism prevails at temperatures lower than 2500 K and the “direct adsorption” and “push-out” mechanisms are observed at higher temperatures.