▎ 摘　　要

We study the effect of twist on the electronic structure of H-terminated armchair graphene nanoribbons, for both relaxed and unrelaxed unit cell size. We investigate the band gap change as a function of the twist angle for different ribbon widths. In the case of unrelaxed unit cell size, the band gap closes for smaller twist angles as opposed to relaxed unit cell size. We calculate strain energy as a function of twist angle and show its direct correlation with the reduction of the band gap. Furthermore, the conductance is calculated at arbitrary degree of torsion. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3606553]