Stability and cap formation mechanism of single-walled carbon nanotubes

We use tight-binding total-energy calculations to investigate the energetics and the cap formation mechanism of single-walled carbon nanotubes. The present calculations of the edge energy and strain energy suggest the growth of armchair nanotubes to be energetically more favorable than the growth of zigzag nanotubes. The cap formation at the edge of both nanotubes is animated by the tight-binding molecular-dynamics simulations. The cap formation is immediately followed by the pentagon formation at the edge of both tubes. The role of transitions metals is further discussed.