Fig. 6: Band structures without horizontal dimerization.

a The same phase diagram in Fig. 1b. b, c Band structures for open circles in a: b for the orange circle and c for the blue circle. In the absence of dimerization, the formation of the four Dirac points is the same for single- and double-gap phases as shown in b and c. The parameters (α/t, δ/t) are (0.2, 0.0) for b and (0.8, 0.0) for c.