Effect of twisting deformation on electronic structure and optical properties of gold-doped black phosphorene

The first-principles method based on density functional theory is used to study the effect of torsion deformation on the electronic structure and optical properties of gold-doped black phosphorene. The results show that the electronic structure of the gold-doped black phosphorene system is more sensitive to torsion deformation than that of the intrinsic black phosphorene system under torsion. The analysis of the energy band structure indicates that intrinsic black phosphorene is a direct band gap semiconductor. After being doped with gold, it can realize its transformation from semiconductor into metal. After the gold-doped black phosphorene system is twisted by 1 degrees, the band gap is opened and becomes an indirect band gap semiconductor. As the torsion angle increases, the band gap of the intrinsic black phosphorene system increases slowly, while the band gap of the gold-doped black phosphorene system first decreases, then increases, and then decreases. From the analysis of the density of states, it is found that when the torsion angle changes from 0 degrees to 5 degrees, the intrinsic black phosphorene system has a strong sp orbital hybridization. The s orbit and p orbit contribute to the conduction band and the valence band, but the p orbit is better than the s orbit. The contribution to the total density of states is more, and the s orbital, p orbital and d orbital of the gold-doped black phosphorene system all contribute to the total density of states. From the analysis of optical properties, it is found that compared with the intrinsic black phosphorene system with a torsion angle of 0 degrees, the intrinsic black phosphorene twisted system exhibits a blue shift at the absorption peak and reflection peak, and the gold-doped black phosphorene twisted system exhibits a blue shift in both absorption peak and reflection peak. Both the absorption peak and the reflection peak are red-shifted.