Fig. 1: Schematic and Brillouin zone (BZ) of the Haldane model.
From: Topological bulk solitons in a nonlinear photonic Chern insulator
a Schematic of the Haldane model with a real nearest-neighbor (NN) hopping (black lines), a complex next-nearest-neighbor (NNN) hopping (red and blue arrows), and on-site staggering energies (white and black circles). The rhombus with green lines is the unit cell. b BZ of the Haldane model, where K and K′ are the two valleys.
