Size, shape and structure dependent cohesive energy and phase stability of metallic nanocrystals

A model to account for the size, shape and structure dependent cohesive energy of metallic nanocrystals is developed in this contribution. It is predicted that the cohesive energy of nanocrystals decreases with decreasing the crystal size in specific shape, and decreases with increasing the shape factor in specific size. Furthermore, the model can be applied to predict the size and shape dependent phase stability of nanocrystal. To take Cr nanocrystal as an example, we found that there exists FCC structure for Cr crystal (the bulk structure is BCC) when the crystal size is small enough, and critical size of phase transition ranges from 249 to 824 atoms due to crystal shape variation, which is consistent with the corresponding experimental results.