Controllable irregular phenomenon induced by Ag atomic segregation on the melting of (AgPd)₅₆₁ bimetallic clusters

摘要

This paper studies the melting of Ag–Pd bimetallic clusters with different Ag concentrations and atomic distributions by using molecular dynamics simulation with a general embedded-atom method. The melting of a cluster with 45 % Ag atoms distributing in the core was compared with that of 45 %, 15 % Ag on the surface and 15 % Ag in the core. It is found that the energy variation with the increasing temperature is strongly related to the Ag atomic segregation, due to the reason that there is a competition between the decreased energy induced by the atomic segregation and the increased energy as the temperature increases. The melting of the Ag-core clusters with different Ag concentrations from 5 to 55 % Ag was further explored. It is found that the irregular variation of energy occurred that the atomic energy increases, keeps unchanged or decreases with the increase of the temperature. Furthermore, the irregular phenomena of the melting were induced by the Ag concentrations. This gives a new method to tune the melting in bimetallic clusters.