Scenarios of structure formation in four-component nanoparticles: atomistic simulation

Abstract

Scenarios of structure formation in four-component nanoparticles are considered. The objects of study were Au-Cu-Pd-Pt nanoparticles containing N = 400, 800, 1200, 1600, 2000, 4000 atoms of the stoichiometric composition Au3CuPd12Pt4. Two alternative modeling methods were used: the molecular dynamics and the Monte Carlo. The interaction between atoms was described by the tight binding potential. The phase transition temperatures for the nanoparticles under study were determined. It has been established that the melting and crystallization temperatures depend both on the size of nanoparticles and on the rate of temperature change (by using the molecular dynamics method). The melting rate of nanoparticles has little effect on the melting temperature, while increasing the cooling rate significantly reduces the crystallization temperature and slows down the segregation processes. The process of coalescence of two four-component nanoparticles was modeled. During the process of coalescence, significant mixing of atoms of different types does not occur when using the Monte Carlo method, which leads to some stopping of the growth of the neck at the point of contact, in contrast to molecular dynamics method, where the growth of the neck occurs gradually.

Keywords

• molecular dynamics method
• monte carlo method
• tight-binding potential
• four-component nanoparticles
• structure formation
• melting and crystallization temperatures