Size and composition effect on structural properties and melting behaviors of Cu-Ag-Au ternary nanoalloys

摘要

Structural optimization of ternary Cu-Ag-Au nanoalloys with 38 and 55 atoms was performed using the basin-hopping algorithm and the Gupta many-body potential was adopted to model interatomic interactions. The optimization results show that, while the Ag atoms prefer to segregate to the surface, Cu atoms were located at the core of the nanoalloy due to the higher surface and cohesive energy, whereas Au atoms mainly are located on the surface of the nanoalloys. It is found that the size has little effect on the segregation phenomena of Cu, Ag and Au atoms in the Cu-Ag-Au ternary nanoalloy. We estimated the melting temperatures of Cu-Ag-Au ternary nanoalloys using caloric curves and Lindemann index data obtained from classical molecular dynamics (MD) simulations. The results showed that the melting temperature is closely associated with the size and composition of the nanoalloys and varying the composition gives rise to a fluctuation in melting temperatures. Also, structural evolutions and dynamical behaviors of nanoalloys in melting process are investigated with root mean square displacement (RMSD).