Laser-Induced Spin-Lattice Coupling and the Emergence of Ferrimagnetic State in Kagome Metal RbV3Sb5.

Light-matter interactions in frustrated Kagome metals provide a platform for investigating hidden quantum states, while the microscopic origin of non-equilibrium symmetry breaking remains under discussion. Here, spin-lattice coupling in RbV3Sb5 is found to induce rotational and time-reversal symmetry breaking through enhancement of a single-QM phonon mode. The resulting anisotropic lattice distortion lifts geometric frustration and stabilizes a non-equilibrium ferrimagnetic phase accompanied by an intrinsic anomalous Hall effect. The calculations further indicate that coherent phonon excitation can modulate symmetry under strong optical fields without requiring orbital antiferromagnetism or extrinsic perturbations. The induced spin polarization, together with spin-orbit coupling, generates finite Berry curvature in momentum space and modifies the topological electronic structure. These results provide insight into the interplay among spin, lattice, and charge degrees of freedom in non-equilibrium correlated states of Kagome materials and may be relevant for optically controlled spintronic functionalities.