▎ 摘　　要

Density functional theory is used to study the electronic states at the zigzag edges of graphene terraces, considering bare edges and H, F, Cl, NH2 terminations. In contrast to the H and F terminations, periodic structural reconstructions are observed for the Cl and NH2 terminations due to interaction between the terminating atoms/groups. It is shown that the Cl termination of the edges leads to p-doping of the terraces, whereas NH2 termination results in n-doping.