Figure 2

Band structures along the armchair edges of the planar Sb (a) and Bi (b) honeycombs. Structures of the nanoribbons with armchair (c) and zigzag (f) edges. Band structures for the zigzag ribbons for Sb (d) and Bi (e). Contribution of the right (left) hand side edge is marked with red crosses (blue circles). The filled yellow region denotes the bulk bands. Sizes of red crosses and blue circles are proportional to the contribution of the edges.