TO THE PROBLEM OF STABILITY/INSTABILITY OF BIMETALLIC STRUCTURES Co (CORE)/Au (SHELL) AND Au (CORE)/Co (SHELL): ATOMISTIC SIMULATION
In this work, we performed atomistic modeling of the behavior of Co (core)- Au (shell) and Au (core)-Co (shell) during thermal exposure in order to study the stability/instability problem for the above nanostructures using the tight binding potential and two alternative computer programs based on the molecular dynamics and Monte Carlo methods. It has been shown that both the Co (core)- Au (shell) and Au (core)- Co (shell) structures can be stable. However, molecular dynamics results predict a short-term decay of Au<sub>2500</sub> (core) / Co<sub>2500</sub> (shell) nanostructures in a high temperature region followed by a self-assembly, while the Monte Carlo method predicts the appearance of defects - cavities in the particle core and on the boundary between two components. It is concluded that the size effect can be the main factor determining stability/instability for the Co (core)- Au (shell) and Au (core)-Co (shell) structures.