▎ 摘　　要

We studied the electronic properties of graphene nanoribbons with several edge structures under a parallel electric field using density functional theory with the effective screening medium method. Our calculations showed that the edge atomic sites of the nanoribbons with zigzag-shaped edges anomalously screen the electric field; the electrostatic potential oscillates rapidly, leading to over-screening in the vicinity of edge C atomic sites. We also found that the penetration depth of anomalous screening depends on the edge structure of nanoribbons. (C) 2014 The Japan Society of Applied Physics