Structures and properties evolution with size of ScN nanocrystals: A first-principles study

► The formation of cage-like Sc4N4 units is energetically favorable in Sc2nN2n nanocrystals. ► Small-size nanocrystals prefer to form the rectangular-like wire structures with the repeated cage-like Sc4N4 units. ► Large-size nanocrystals exhibit compact rectangular-like or cubic-like configurations. ► The trends in some properties evolution with size of Sc2nN2n nanocrystals are identified.