Light-Induced Metastable Disordered Spins in the Kitaev Candidate α-RuCl₃

SPICE Young Research Leaders Group Workshop: Magnetism in van der Waals materials: current challenges and future directions, July 8th - 10th 2025

Hamoon Hedayat

We investigate the ultrafast magnetic dynamics of the Kitaev spin liquid candidate α-RuCl₃ using time-resolved magneto-optical spectroscopy. Femtosecond photoexcitation across the Mott-Hubbard gap creates holon-doublon pairs that rapidly suppress the zigzag antiferromagnetic order, leading to a state of metastable disordered spins that persists for up to nanoseconds. This non-thermal state reflects the strong interplay between charge and spin degrees of freedom in this spin-orbit coupled Mott insulator. Upon relaxation, the system exhibits a universal compressed-exponential recovery, consistent with domain-wall propagation governed by the Fatuzzo mechanism. Our findings reveal how ultrafast charge excitation can transiently destabilize proximate Kitaev magnetism and enable optical access to non-equilibrium magnetic states in strongly correlated quantum materials.