First-principles study on stability and magnetism of Ni m Al n (m = 1-3, n = 1-9) clusters

The investigation on the structures, stabilities, and magnetism of Ni(m) Al(n) (m = 1-3, n = 1-9) clusters has been made by using first principles. We found some new ground-state structures which had not been found before. These mixed species prefer to adopt three-dimensional (3D) structures starting from four atoms. All the ground-state structures for the Ni-Al clusters are different from those of the corresponding pure Al clusters with the same number of atoms except for three atoms. The Mulliken population analysis shows that some charges transfer from the Al atoms to the Ni atoms. NiAl n (n = odd number) cations, Ni(2)Al(6) neutral, Ni(2)Al(1) and Ni(3)Al cations and anions, and Ni(3)Al(5) anion have the magnetic moments of 2 μ B. The magnetic moments of NiAl(4) and NiAl(6) cluster neutrals and cations are 2 μ B and 3 μ B, respectively. All the other cluster neutrals and ions do not have any nontrivial magnetic moments. The 3d electrons in Ni atoms are mainly responsible for the magnetism of the mixed Ni-Al clusters.