Metallic nanostars as a new object for atomistic simulation

The thermal stability of gold nanostars with two types of initial morphology: a great dodecicosacron and a great inverted snub icosidodecahedron was studied. The initial nanostar configurations were obtained using the Atomsk program, followed by structural relaxation. Thermally induced stress was simulated using the Monte Carlo method (Metropolis scheme). Interatomic interactions were described by the tight-binding potential. Critical destabilization temperatures, which increase with increasing size for both types of the initial morphology, were determined. Patterns of structural segregation during thermally induced stress up to the melting temperature were also established. Despite the dominance of the local FCC structure in the central part of the nanostars, the nature of the distribution of local HCP structure differs for the considered types of the initial morphology up to the melting temperature. Thermal degradation was shown to begin with «multiple rays» of nanostars, where the local atomic density is lower than the surface average one. The results allow us to predict the stability of anisotropic nanoparticles for photothermal applications.