Fig. 4
From: Double-Gated Nanohelix as a Novel Tunable Binary Superlattice
a Band gap size between ground and first subbands as a function of Ag (C⊥) plotted as dashed red (dot-dashed green), here Bg=0.25. The diagrams indicate the influence of the different perturbations on the isolated DQW unit cell and eigenstates. b–c Band gap size between first and second subbands indicated via a 2D density plot as a function of; b Ag and Bg for C⊥=0, and c Ag and C⊥ with fixed Bg=0.25. b Adjacent isoenergy contour lines indicate a difference of 0.17, with zero gap given by the dot-dashed red line for \(A_{g}=\sqrt {B_{g}}\), while c the difference is 0.13 with zero gap at the centre of the smallest semi-circle contour (0.5,0). The diagrams sketch the isolated DQW and eigenstates. Hybridization does not occur between the s-like and p-like resonant localized individual well states in b, but does in c due to the electric field changing one barrier with respect to the other