▎ 摘　　要

The narrower the width of the graphene, the higher the impact of the atomic edge structure on its electronic properties. Here, we have performed computer simulations for the mechanical tearing of graphene to form a graphene nanoribbon (GNR) and identified the atomic edge structures. The simulations clearly show that shear force applied to graphene results in armchair edge structures, independent of the tearing direction. Even if the tearing is initiated along the zigzag direction, the initial zigzag edge structures are immediately followed by the armchair edges. Thus, the GNRs with the atomically flat armchair edges can be formed through a wide range of conditions, which is essential for the production of low-dimensional nanodevices with the same specifications.