Strain engineering in novel α-SbP binary material with tensile-robust and compress-sensitive band structures

Antimony phosphorus in the alpha phase (α-SbP) is a novel two-dimensional binary material with suitable band gap and environmental stability, it has attracted attention for its promising applications in the field of optoelectronics. In this work, the electronic and optical properties of α-SbP monolayer under biaxial strain have been studied by first principles calculation method based on density functional theory. It is found that when the tensile strain is applied, the band gap value of monolayer SbP increases firstly and then decreases under tensile strain, but the whole band gap value fluctuated is controlled within 0.08 eV. However, in the process of applying compressive strain, the band gap value decreases linearly with the strain value, and semiconductor-metal transition occurs at about −5% strain value. This is due to the difference in coupling between Sb and P atoms. Its optical properties under different strains are analyzed in detail, and it is found that the optical properties of SbP changed little under tensile strain, the light absorption peak is mainly concentrated in the ultraviolet region. In contrast, the compressive strain significantly adjust the optical properties of SbP. The innovation of this work is that the optoelectronic properties of SbP are studied by means of biaxial strain regulation. We find that the optoelectronic properties of SbP are robust to tensile strain. On the other hand, compressive strain has a significant effect on the photoelectric properties of SbP, and semiconductor-metal phase transition occurs. The research work in this paper provides theoretical support for the applications of monolayer α-SbP as a robust tensile and flexible compression material in optoelectronic nanodevices.