Effect of size on energy and elastic constants of Ni nanoparticles studied using the embedded-atom method

摘要

Using the embedded-atom method potential, the energy and elastic constants of Ni nanoparticles are investigated as a function of size. It is found that a simple formula derived from the total energy can be used to explain the change characteristics of the size-dependent energy and C_(11) and C _(44) of Ni nanoparticles. The change characteristics of the size-dependent C_(12) are slightly different from the situation of C_(11) and C_(44) and they perhaps depend on its strain character when the nanoparticle is larger than ～2.0 nm in size. It is also found that a transition occurs from a fast change of these size-dependent properties to a slow one. Such a transition occurs at ～1.5 nm in size for the nanoparticles, i.e. the energy and elastic constants of Ni nanoparticles show approximately no change as long as their size is larger than 2 nm. It is also demonstrated that when the size of the nanoparticle is large enough (>20 nm) the calculated elastic constants and the cohesive energy are in agreement with those of their respective bulk counterpart.