Electric field tuning of dynamical dielectric function in phosphorene

We present electric field effects on the optical field-dependent dielectric function of phosphorene. We use a two-band model and the Kubo formula to obtain refractive index and absorption coefficient. From our findings, the refraction (absorption) along the armchair direction is smaller (larger) than the zigzag direction for the optical energies close to and larger than the band gap. Moreover, we find that for frequencies beneath the band gap, dynamical dielectric function decreases with the electric field independent of the orientation, whereas there is a strong anisotropic treatment above the band gap. © 2019 Elsevier B.V.