First-principle study of ultrafast dielectric response of monolayer phosphorene to femtosecond laser

In this paper, we studied the ultrafast response of the dielectric properties of monolayer phosphorene to femtosecond laser pulses by employing time-dependent density functional theory. The simulation results showed that the dielectric function of monolayer phosphorene exhibited a negative divergence of its real part at low frequency and a remarkable "quasi-exciton" absorption peak of its imaginary part after femtosecond laser irradiating. It was inferred that this type of response was induced by electron-hole pairs excited by the femtosecond laser. The nonlinear response of excited current by femtosecond laser in monolayer phosphorene was also investigated. The plasma oscillation and breakdown in monolayer phosphorene was revealed. Moreover, we showed how the degrees of freedom (intensity and wavelength) of the laser pulse could be helpful for the manipulation of the system transient response.