Structures and magnetic properties of Ni ( n = 36-40) clusters from first-principles calculations.

A genetic algorithm (GA) coupled with a tight-binding (TB) interatomic potential is used to search for the low-energy structures of medium-sized Ni ( n = 36-40) clusters. Structural candidates obtained from our GA search are further optimized with first-principles calculations. The medium-sized nickel clusters ranging from 36 to 40 atoms are found to favor the double-icosahedron-based structures with a Ni core (a pentagonal bipyramidal structure) except Ni cluster. The lowest-energy structure of Ni can be considered to be a magic cluster, which is a typical face-centered cubic structure with large stability and magnetic moment. [ABSTRACT FROM AUTHOR]