Blue shift in the interband optical transitions of gated monolayer black phosphorus

摘要

The anisotropic frequency-dependent optical conductivity of single-layer puckered phosphorene is studied, and also its dependence on the electrostatic gating of the top and bottom sublayers. The effective Hamiltonian within the (k) over right arrow.(p) over right arrow approximation is used to obtain the electronic band structure from which the interband optical transitions are evaluated using the Kubo formula. Inherent asymmetry in the dispersion energy of carriers along the armchair and zigzag edges gives rise to anisotropic optical features. The bandgap increases with gate voltage resulting in absorption at higher optical energies along the armchair edge, which is the so-called blue shift, while along the zigzag edge such a shift is not significant. The temperature and exciton effects on the interband response are concisely discussed. These results provide new insights which render phosphorene attractive for optoelectronic devices. Published under license by AIP Publishing.