▎ 摘　　要

We present a systematic study of 3d transition-metal (TM) atomic chains adsorbed on a line defect consisting of octagonal and pentagonal carbon rings embedded in a perfect graphene sheet. The results suggest that Sc, Ti, V, Cr and Mn atoms can be spontaneously adsorbed at octagonal sites and form an atomic chain along the line defect in graphene, while Fe, Co and Ni atomic chains are adsorbed at pentagonal sites. Moreover, the Sc, Ti, V, Cr, Mn and Fe chains embedded in line defect of graphene structures show half-metallic characters. These results propose a new route to explore the potential applications of the system in spintronic devices.