Intrinsic and extrinsic strain induced structural change of zigzag graphene nanoribbon

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 XC bonds elongated substantially when X are p-type dopants. The height of apophysis and the length of XC 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.

► We study a zigzag graphene nanoribbon doped by Be, O, Al, Si and P atoms.
► The structures are greatly different for various doping charge states.
► We propose a volume model to explain this structural difference.
► The doped ribbons under extrinsic strain exxexx and eyyeyy are studied.