Melting behavior of Ir-Ag-Au nanoalloys: a molecular dynamic study

Abstract

ABSTRACT MD simulations have been employed to investigate the melting behaviour of Ir-Ag-Au nanoalloys with two different systems: Ir43AgnAu12-n (n = 0-12) and some specific nanoalloys (Ir1Ag54, Ir1Au54, Ir13Ag42, Ir13Au42, Ir1Ag42Au12, and Ir13Ag12Au30). Energetically optimal homotops obtained with the local optimizations were taken as the initial configurations in this simulation. The local optimization results of the Ir-rich nanoalloys demonstrate that Ag and Au atoms occupy the vertex position on the surface. Caloric curve, heat capacity, and Lindemann index methods were used for examining the thermal stability of the Ag-Au surface structure. It was obtained that the melting temperature of Ir-rich nanoalloys depends on the composition. For melting transitions of Ir-rich nanoalloys, two types were identified: structural deformations around the melting temperature and sudden jump. It was discovered that the melting mechanism of some specific nanoalloys generally has surface and inner shell melting.