Size and Structure Dependent Elastic and Dynamic Properties of Multi-Shell Nickel Nanowires

Using molecular dynamics (MD) simulations with a Sutton-Chen many body potential, we have studied the mechanical properties of atomic-sized nickel nanowires along [110] direction. The binding energies are approximately degenerate for both helical and crystalline structures in terms of MD based simulated annealing method. Constant strain based simulation and Parrinello-Rahman constant-pressure algorithm were used to investigate the elastic and dynamic properties of the obtained nanowires. The sized and structural dependence of Young's moduli is clarified. We also confirm that the interaction between the surface and the core of nanowires have relative small effects on their stiffness, in spite of the fact that the interaction energy is sufficiently large. The mechanical response of nanowires to the external loading is further discussed in terms of the theoretical result of an ideal free elastic stick based from the continuum-medium mechanics.