▎ 摘　　要

Energetics, spin polarization, and electron states of graphene nano-ribbons (GNRs) are investigated by using the density functional theory. To consider realistic shapes of GNRs in nature, we focus on the nearly zigzag-edged GNRs (NZE-GNRs) which have finite-length zigzag edges connected by another short zigzag edge (kink). Through the systematic calculations, we have clarified roles of nano-shapes of NZE-GNRs in its stability, the spin polarization, and the electron states. Edge states localized near the zigzag edge, the flat bands, and the consequent spin-polarized ground states exist when NZE-GNRs have long enough zigzag edges or wide enough width. In contrast, we have found that the large kink size hinders their appearance. We have also calculated the edge formation energies of various NZE-GNRs. The relative stability of the edge is enhanced when the zigzag edge is short or the width is narrow.