First principles study on structural and magnetic properties of small and pure carbon clusters (Cn, n 5 2–12)

We have demonstrated the structural and magnetic properties of small carbon clusters (Cn, n = 2–12) in the framework of collinear approximation using density functional theory. The calculations were performed for amorphous, linear, and ring carbon clusters using full-potential local-orbital method. We have obtained stable structures, total energies, total magnetic moments, and HOMOLUMO energy gap of these clusters. We have found that the amorphous carbon clusters with minimum energy are not magnetic clusters, whereas their less-stable isomers with special configurations are ferromagnetic objects. Two robust magnetic moments were found for C5 carbon ring (6μB) and for pentagonal pyramid C6 structure (4μB).