Gap Engineering and Wave Function Symmetry in C and BN Armchair Nanoribbons

There are many ways of engineering the band gap of nanoribbons, including application of stress, electric field, and functionalization of the edges. In this paper, we investigate separately the effects of these methods on armchair graphene and boron nitride nanoribbons. By means of density functional theory calculations, we show that, despite their similar structures, the two materials respond in opposite ways to these stimuli. By treating them as perturbations of a heteroatomic ladder model based on the tight-binding formalism, we connect the two behaviors to the different symmetries of the top valence and bottom conduction wave functions. These results indicate that opposite and complementary strategies are preferable to engineer the gap width of armchair graphene and boron nitride nanoribbons.