Electronic structure and optical properties of two-dimensional antimony: A first principle study

Abstract

Two-dimensional (2D) antimonene has similar physical and chemical properties as graphene, BP, MoS2 and other typical 2D materials. It has shown good application prospects in many fields such as nano-optoelectronics, biomedicine and attracted wide attention of the scientific community. In this paper, the crystal structure, electronic structure and optical properties of antimony with few-layers have been systematically studied by the first-principles method based on density functional theory. The results show that the bond lengths of antimonene in few-layers are shorter than those of bulk except monolayer, and the bond lengths and bond angles are smaller with the decrease of layers. In addition, with the increase of the number of layers, the antimonenes are transited from semiconductor to conductor, in which the monolayer is a semiconductor with indirect band-gap, the two and three layers are transitional states, and the four layers are completely transitional to metal state. This conclusion has been proven by PBE method, hybrid HSE06 method and van der Waal’s correction. It is also consistent with the results of density of states. The dielectric function analysis of the 2D antimonenes shows that, with the increase of layers, the polarization ability of antimonenes is stronger, and the static dielectric constant is larger. The imaginary part of dielectric function changes with the change of energy, and with the increase of the number of layers, the curve red-shifts and the frontal value increases. Overall, in the low and high energy regions of photons, with the increase of layer number, the reflection coefficient of antimonene is relatively larger, and in the middle region, the phenomenon of relative aggregation occurs. In addition, the absorption curve corresponds to the imaginary part curve of dielectric function. With the increase of the layer number, the red shift also occurs. For long wavelength light, the fewer number of layers, the worse absorption. But for the ultraviolet region, they all have good absorption. This conclusion is helpful for us to understand the physical and photoelectric properties of two-dimensional antimonene with few layers more comprehensively, and provides a good theoretical basis for the application and research of antimony photoelectric materials and devices.