First-principles total-energy electronic-structure calculations in density functional theory were performed for carbon nanotubes containing a topological line defect consisting of pentagon and octagon rings. It was found that the ground state of the nanotubes with the topological line defect was ferromagnetic, with a small but finite magnetic moment of about 0.04μB. Detailed analyses of energy bands and spin densities unequivocally revealed the nature of the ferromagnetic spin ordering, which was associated with the peculiar edge-localized states of graphite flakes.

Ferromagnetic Spin Ordering on Carbon Nanotubes with Topological Line Defects. S.Okada, K.Nakada, K.Kuwabara, K.Daigoku, T.Kawai: Physical Review B, 2006, 74[12], 121412