First-principles calculations on the structures, magnetic, and electronic properties of the (Fe2N)m (m = 1–4) and (Fe3N)n (n = 1–3) clusters

The structures, magnetic, and electronic properties of the ground-state (Fe2N)m (m = 1–4) and (Fe3N)n (n = 1–3) clusters have been investigated by using first-principles. The structure of the (Fe2N)m and (Fe3N)n clusters is a compromise that the N atoms approach more Fe atoms and the N atoms repel each other. The structural stabilities of the (Fe2N)m and (Fe3N)n clusters increase with the increasing of the N ratio except for the Fe6N3 clusters. The (Fe2N)m (m = 1–4) and Fe9N3 clusters exhibit more kinetic stabilities than pure iron clusters. The N substitution can decrease the average spin densities of small iron clusters except for the Fe6N2 and Fe8N4 clusters. The Fe–N bonds exhibit certain covalent bond characteristics.