Floquet topological phase transitions and chiral edge states in a kagome lattice

•A kagome lattice under a circularly-polarized driving field is studied.•The band structures and chiral edge states are studied via exact Floquet method.•Various modifications of the Floquet band structure are found.•Floquet topological phase transitions appear in both off- and on-resonant cases.

The Floquet topological phases and chiral edge states in a kagome lattice under a circularly-polarized driving field are studied. In the off-resonant case, the system exhibits the similar character as the kagome lattice model with staggered magnetic fluxes, but the total band width is damped in oscillation. In the on-resonant case, the degeneracy splitting at the Γ point does not always result in a gap. The positions of the other two gaps are influenced by the flat band. With the field intensity increased, these two gaps undergo closing-then-reopening processes, accompanied with the changing of the winding numbers.