Linear and Nonlinear Optical Responses in Kitaev Spin Liquids

Understand

We theoretically study THz-light-driven high-harmonic generation (HHG) in the spin-liquid states of the Kitaev honeycomb model with a magnetostriction coupling between spin and electric polarization.

• To compute the HHG spectra, we numerically solve the Lindblad equation, taking account of the dissipation effect.
• We find that isotropic Kitaev models possess a dynamical symmetry, which is broken by a static electric field, analogous to HHG in electron systems.
• We show that the HHG spectra exhibit characteristic continua of Majorana fermion excitations, and their broad peaks can be controlled by applying static electric or magnetic fields.