Structures of ultrathin copper nanowires encapsulated in carbon nanotubes

We have investigated the structures of copper nanowires encapsulated in carbon nanotubes using a structural optimization process applied to the steepest descent method. The results showed that the stable morphology of the cylindrical ultrathin copper nanowires in carbon nanotubes is multishell packs consisting of coaxial cylindrical shells. As the diameter of carbon nanotubes increased, the encapsulated copper nanowires have the face-centered-cubic structure as the bulk. The circular rolling of a triangular network can explain the structures of ultrathin multishell copper nanowires encapsulated in carbon nanotubes.