Realization of topological phase in a chiral honeycomb lattice model

We investigate topological properties of a chiral honeycomb lattice model with next-nearest-neighbor hoppings characterized by the reflection symmetry breaking. Topological nontriviality is detected by analyzing effective Dirac Hamiltonian, and confirmed by numerical and analytical study of the emergence of topological edge states at the boundaries between topologically distinct regions. We have also discovered that a novel asymmetric edge current attributable to chirality can be excited without any involved phase shifts in input sources to pick up one of the pseudospin components.