Floquet engineering of Kitaev quantum magnets*

Ultrafast light-matter interaction offers opportunities to control the physical properties of quantum materials. We apply this concept to the Kiteav quantum magnets such as RuCl3 and irridates. These quantum magnets are promising candidates for the realization of the Kiteav quantum spin liquid which hosts highly nontrivial fractionalized excitations. However, the realistic spin Hamiltonian for these materials includes terms that can perturb the system aways from the long-sought for the quantum spin liquid phase. In this work, we propose to use light to tune magnetic interactions in spin-orbit coupled Mott insulators relevant for Kiteav quantum magnets.  We derive an effective spin Hamiltonian from multiple orbital spin-orbital coupled Hubbard model coupled to a circularly polarized light using the Floquet theory. We demonstrate that magnetic interactions favorite for quantum spin liquid can be achieved by tuning the frequency and amplitude of the light. Furthermore, an effective Zeeman field is generated by the light due to the inverse Faraday effect. Our work points to a promising route to stabilize quantum spin liquid by coupling quantum magnets to light.