First-Principles Study of the Carbon-Oxygen Nanotubes

Abstract

This paper studies the deformation characteristics of a platinum nanowire with triangular and hexagonal cross-sectional shapes, using molecular dynamics (MD) simulation. Together with a study performed on the circular and rectilinear shaped nanowire, this paper investigates and summarizes the effects that cross-sectional shape has on the ductility, stiffness and tensile strength of a nanowire with characteristic size of about 1.5 nm. The many-body Sutton-Chen interatomic potential was used for this simulation, and the velocity-Verlet algorithm was adopted for time-integration. The Berendsen loose-coupling thermostat was used for maintaining the simulation temperatures at 50 K and 300 K. The canonical ensemble of the atomic trajectories was used to compute the system properties. It was found that, due to the lack of axis-symmetry of the triangular and hexagonal shaped nanowires, they had the tendency to reorganize to an alternate stable axis-symmetrical crystal configuration during the stretching process. This enabled it to achieve an overall 40% higher tensile strength, and a 30% and 50% higher Young's modulus for the hexagonal nanowire at 50 K and 300 K respectively. The contribution to nanowire ductility was dependent on the type, development length and stability of the substructure formed at the necked area. The magnitude of contribution towards ductility was found to be proportional to the number of sides of the cross-sectional shape.