Nonlinear Polarization and Low-Dissipation Ultrafast Optical Switching in Phosphorene

Fundamental limits to the computation using silicon-based devices stimulate other emerging and viable alternatives. Manipulation of the electrical and optical properties with the ultrafast and intense electric fields offers one of such alternatives. Here, we study the interaction of high-intensity pulsed femtosecond laser of various intensities and carrier frequencies with a monolayer phosphorene using the real-time real-space time-dependent density functional theory. The nonlinear induced currents are entirely reversible but are phase-shifted compared to low-intensity lights within the period of incident laser. We observe optical Kerr effect associating the changes in the number of free charge carriers with the change in the refractive index of the material, which subsequently characterizes the material's ability of dielectric switching. The transient changes in refractive index are reversible up to a certain threshold, suggesting that the properties can be switched on the timescale of an optical period, enabling the possibility of operating solid-state electronic devices at optical frequencies. The amount of irreversibly transferred energy into the system is found to be much smaller than that of the state-of-the-art metal-oxide field-effect transistor, thereby making phosphorene a promising candidate for high-speed electronics