The Haldane Model in a Magneto-optical Honeycomb Lattice

A two-dimensional honeycomb lattice composed of gyrotropic rods is studied. Beginning with Maxwell's equations, a perturbed Wannier method is introduced which yields a tight-binding model with nearest and next-nearest neighbors. The resulting discrete model leads to a Haldane model and as such, topologically protected modes, associated with nonzero Chern numbers are supported. Changing the radii of the rods allows for the breaking of inversion symmetry which can change the topology of the system. This model describes experimental results associated with topological waves in magneto-optical honeycomb lattices. This method can also be applied to more general Chern insulator lattices. When on-site Kerr type nonlinear effects are considered, coherent soliton-like modes are found to propagate robustly through boundary defects.