▎ 摘　　要

We investigate the energetics and electronic structure of graphene nanoribbons (GNRs) with structural torsion in terms of their torsion angles and edge shapes using the density functional theory with the generalized gradient approximation. The structural torsion with the period of nanometer scale does not cause the increase of the total energy of GNRs up to the torsion angle of 20 degrees. On the other hand, the total energy with respect to the torsion is weakly dependent on the edge angle. The GNR with zigzag edges is the most flexible against the structural torsion, while those with armchair and chiral are robust. Electronic band structures of GNRs are also insensitive to the structural torsion, because the local atomic structure retains its flat conformation up to the largest torsion. (c) 2019 The Japan Society of Applied Physics