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.