On the optimal conditions for the formation and observation of long icosahedral nanowires of aluminium, nickel and copper

This article presents a statistical study based on molecular dynamics simulations of the formation of icosahedral nanowires from the breakage of Al, Ni and Cu nanowires. These icosahedral nanowires, which show large stability, are created by the emergence of new units of 5 + 1 atoms (atomic pentagonal rings plus one atom at the top) due to the anisotropic growing mechanism induced by nanowire stretching. The appearance of each new 5 + 1 atomic set (an inelastic atomic rearrangement) during the stretching is matched with a sudden decrease of the force exerted on nanowire extremes. We have also demonstrated that the icosahedral formation is favoured when stretching takes place along the [1 0 0] and [1 1 0] crystallographic directions. We demonstrate that, as result of a balance between two competitive mechanisms, there exists an optimal temperature that provides the larger icosahedral nanowires production for each metallic species. (paper)