Tunable nonlinear optical response of silicene in terahertz regime
The nonlinear optical response of silicene in terahertz (THz) regime is theoretically studied. Since the intrinsic spin-orbit coupling gap of silicene is in the order of 1 THz, the optical response in few THz frequency regime is strongly enhanced by linear and nonlinear conductivity peaks. Furthermore, these conductivity peaks are gate-tunable. The frequency-tripling nonlinear optical current can be significantly larger than the single-frequency current under a moderate electric field strength of 1000 V/cm. This suggests that tunable strong THz frequency-tripling effect can be achieved in silicene.