Mechanical and electronic properties of 2D green phosphorene, a first-principles study

Recently, a phosphorus isomer named green phosphorus was theoretically predicted with a similar interlayer interaction compared to that of black phosphorus, thus indicating that individual layers can be mechanically exfoliated to form two-dimensional (2D) layers known as green phosphorene. The 2D structure shows high stability and was predicted to have a direct band gap up to 2.4 eV. First-principles density functional theory calculations were used to investigate the mechanical properties and strain effect on electronic band structure of the 2D green phosphorene along two perpendicular in-plane directions. Remarkably, it was found that the material can sustain a tensile strain in the armchair direction up to a threshold of 35% which is larger than that of black phosphorene, suggesting that green phosphorene has more puckered structure. The results also showed that the Young’s modulus and Poisson’s ratio in the zigzag direction are four times larger than those in the armchair direction, which confirms the anisotropy of the material. Furthermore, uniaxial strain can trigger the direct-indirect bandgap transition in the material, and the critical strains for the bandgap transition are revealed.
[Reference] G. Yang, T. Ma, X. Peng, Applied Physics Letters 112, 241904 (2018)