Study on the Phase Transition Behavior of Ni Nano-clusters using Molecular Dynamics Simulation

Minwoong Joe, Sang-Pil Kim, Kwang-Ryeol Lee
 

Structural phase transition of Ni nanocluster from cuboctahedron to icosahedron at 1100 K is investigated by means of molecular dynamics simulation. Radial distribution function and potential energy of each atom are calculated to study the transition phenomena in detail. At 1100 K, potential energy of interior atoms in the cluster is increased before the transition, while the periodicity of a0 in the radial distribution function is broken. Thus the interior atoms partially lose its crystallinity in advance of the transition. Rather potential energy of the surface starts to decrease relatively so much by changing the surface structure to icosahedron at/after the transition. Consequently, the system energy is decreased. Minimizing surface energy enables Ni nano cluster to drive the transition. In addition, the interior energy is increased to as much as that of icosahedron prior to the transition.