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|Paper IPM / Physic / 15352||
We investigate the optical absorption and transmission of few-layer phosphorene in the framework of ab initio density functional simulation and many-body perturbation theory in the level of random phase approximation. In bilayer phosphorene, the optical transitions of the valence band to the conduction band is appeared along the armchair direction about
0.72 eV, while it is absent along the zigzag direction. This phenomenon is consistent with experimental observations. The angle-resolved optical absorption in bilayer
phosphorene shows that it is transparent when illuminated by nearly grazing incidence of light. Also, there is a general trend of the increase in the absorption with the increase
of the number of layers, that implies to the light absorptivity can be improved by appropriately increasing the number of layers in few-layers phosphorene.
Our results show that the bilayer phosphorene exhibits greater absorbance compared to the optical absorption of bilayer graphene in the ultraviolet region.
Moreover, the maximal peak in the calculated absorption of bilayer MoS2 is in the visible region, while bilayer graphene and phosphorene are transparent.
Besides, the collective electronic excitations of few-layer phosphorene are explored.
Few-layer phosphorene exhibits a high degree of band anisotropy along the armchair and zigzag directions which are manifested in the collective plasmon excitations.
An optical mode (in-phase mode), which is associated to a two-dimensional plasmon that follows a low-energy √q dependence, and the other one, which is a damped acoustic mode (out-of-phase mode) is rather weak with a linear dispersion, are obtained in few-layer phosphorene.
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