High-temperature Floquet fractional quantum Hall state in a Kagome lattice with photo-inverted hopping

High-temperature fractional quantum Hall (FQH) state is predicted to emerge from geometrically frustrated lattices with topological flat bands, but yet to be demonstrated in realistic systems due to very unusual lattice hopping requirements. Here we show that time-periodic circularly polarized laser (CPL) can effectively invert second-nearest-neighbor kinetic hopping in a Kagome lattice and simultaneously enhance spin-orbit coupling (SOC) in one spin channel, so as to produce an isolated flat Chern band exhibiting high-temperature Floquet FQH effect. CPL-driven monolayer HTT-Pt possesses an unprecedented high flatness ratio Δ/w ~ 40, which paves the way to observing the high-temperature FQH state in realistic 2D systems. Meanwhile, the CPL decreases the SOC strength in the other spin channel to form a chiral Kagome band with a high Chern number. Our approach may be generally applicable to engineering exotic topological quantum states in other crystal lattices.