Optical Properties of Monolayer Bismuthene under Electric Field based on First-principles Calculations

Monolayer bismuthene has extraordinary optoelectronic, catalytic, and biocompatible properties, and potential as a 2D topological insulator. When monolayer bismuthene deposited on the surface of the object to form sufficiently thin, there is a stable form of a low buckling hexagonal structure. If the thickness of the crucible becomes thinner than the Fermi wavelength, there may be a transition from a semimetal to a semiconductor due to the quantum confinement effect. So this could be a promising low-dimensional thermoelectric material. The monolayer bismuthene is a p-type semiconductor, but the hole concentration arising from the intrinsic defects is very low and hard to control. It is found that the optical properties can be changed dramatically by applying external electric field. In this work, the energy band structure, density of states, and optical constants of bismuthene have been calculated using the first-principles calculations based on density functional theory (DFT). With applying an electric field, the optical properties of bismuthene are determined and compared to those calculated from the tight-binding model. The controlled optical properties of monolayer bismuthene may have some applications in optoelectronics, either combined with other 2D or topological materials