Engineering Magnetic Phases Out of Equilibrium in a Strongly Spin-Orbit Coupled Honeycomb Magnet

Strongly spin-orbit coupled quantum magnets such as α-RuCl₃ and Na₂IrO₃ have garnered much attention as possible candidates for realizing a Kitaev spin liquid. Although these materials instead display magnetic order at low temperatures, here we show that irradiation with circularly polarized light can provide a new handle to engineer their competing isotropic and anisotropic magnetic interactions and realize this long sought-after phase. Furthermore, we report that direct consideration of ligand-mediated exchange reveals that the combination of time-reversal symmetry breaking and strong spin-orbit interactions allow for the electron spin degree of freedom to couple to the electric field of the drive causing a weak spin-polarization effect similar to that caused by a magnetic field in the [111] direction. The resultant dynamics can be modeled by an extended Heisenberg-Kitaev model in a magnetic field with photo-induced phases determined by pump parameter dependent magnetic interactions. Our results demonstrate a possible pathway towards realizing the elusive Kitaev spin liquid phase as well as predict a novel magnetoelectric coupling effect arising as a consequence of strong spin-orbit coupling and broken time-reversal symmetry.