Size-dependent cuboctahedron-icosahedron transformations of Co-based bimetallic by molecular dynamics simulation

The size, composition, and atomic distribution of bimetallic clusters influence their structural transformations, so knowledge of these parameters is important to obtain clusters with better properties. The structural transformation from cuboctahedral to icosahedral in cobalt (Co)-based bimetallic clusters was examined using molecular dynamics simulations with an embedded atom method. The results showed that size-dependent structural transformation only occurs in Co-based clusters with a small size (atomic number less than 1415). The structural transformation is diffusionless and occurs instantaneously. The structural transformation is induced by the release of energy and is related to the size, composition, and atomic distribution of the clusters. The transformation temperature rises with increasing copper (Cu) content and cluster size. The core-shell Co-Cu structure displayed a higher transformation temperature and lower released energy than those of the equivalent cluster with a uniform element distribution.