▎ 摘　　要

When a graphene nanoribbon with zigzag edges is doped by a foreign element X, an intrinsic strain will be inevitable introduced into the doped system, which can induce structural change of the system. We find by first-principles calculations that doped nanoribbons could fold at the doping site for n-type dopants and the X-C bonds elongated substantially when X are p-type dopants. The height of apophysis and the length of X-C bonds can be modulated by doping charge states and the extrinsic strains in different directions. We have proposed a model of volume change unexpected contrary with the common expectation to explain this unusual behavior in ribbon structures. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.