Figure 3
Energy spectrum of the finite-sized graphene tube (a) N = 3, M = 124, (b) N = 4, M = 124 and (c) N = 5, M = 124, with flux ϕ. In order to present the zero modes clearly, we separate the upper and lower bands by shifting them up and down with a small amount of energy, respectively. It shows that the zero modes appear and disappear periodically as the flux changes. Here the energy spectrum ε(ϕ) is expressed in units of the hopping constant Δ.
