Fig. 1: 3D stacked HK TB model.
a Illustration of an infinite 3D stacked HK TB model. The unit cell including five nodes is represented by the dashed black rhombus. The intralayer hoppings are ta (green) and tb (blue) in the x − y plane, whereas the interlayer double-helix hopping is tz (brown). Insets: Right view of the cell. b The equivalence between the squared Hamiltonian of the HK circuit and its parents. c The bulk dispersion along the kz direction with (kx, ky) = (4π/3, 0). The dashed blue line indicates the position of the degenerate points. d The first Brillouin zone and the distribution of the Weyl points. The hallow and solid circles represent the Weyl point with the charge ± 1. e Bulk polarization p1 as a function of kz. For TB calculations in c and e, we set ta = 0.5, tb = 1, and tz = 0.5.
