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

ABSTRACT

MD simulations have been employed to investigate the melting behaviour of Ir-Ag-Au nanoalloys with two different systems: Ir₄₃Ag_nAu_12-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.

KEYWORDS:

• Molecular dynamics
• melting behaviour
• structural deformation
• Iridium

Acknowledgments

DL POLY 4 is a molecular dynamics simulation package written by I. T. Todorov and W. Smith and has been obtained from STFC’s Daresbury Laboratory via the website http://www.ccp5.ac.uk/DL POLY.

Disclosure statement

No potential conflict of interest was reported by the author(s).