FLOQUET ENGINEERING OF EXCHANGE INTERACTIONS IN 2D MAGNETIC MATERIALS*

Periodic drive can be used to modify the spin exchange interactions in some magnetic materials. These effects arise mainly due to photon-assisted hopping and can be understood within the framework of periodically driven Fermi-Hubbard model. In real materials, these interactions are usually mediated by the non-magnetic ions, and many different channels are available for the exchange process. We take into account the presence of these ligand ions, and investigate the effects of the periodic drive on magnetic coupling strengths between different neighboring spins in transition metal trichalcogenides for a variety of exchange pathways available in these materials. Additionally, the strength of these interactions depends on the orbitals involved in the superexchange process. We also provide a novel method to control the exchange interactions by manipulating the properties of these orbitals with a periodic drive. In this case, the magnetic coupling strength is altered due to the AC stark shift of the states available for virtual excitations. We discuss two different orbital floquet engineering schemes involving the orbitals of ligand ions and the magnetic ions.