Two-dimensional MgP3 monolayer with remarkably tunable bandgap and enhanced visible-light and UV optical absorptions

Two-dimensional (2D) monolayered magnesium triphosphides (MgP3) is identified as a new member of the 2D XP3 family. Interestingly, a strain less than 8% can induce the bandgap of the MgP3 monolayer changing in a large range from 0.32 to 1.35 eV. On the basis of the first-principles calculations, the geometrical structure of the newfound MgP3 monolayer is relaxed, and the dynamical/thermal stabilities are assured by carrying out calculations of phonon dispersion and ab initio molecular dynamics simulation, respectively. The HSE06 calculations give a direct bandgap of 1.18 eV and enhanced visible-light and UV optical absorptions for the MgP3 monolayer with strain-free. The carrier mobility is higher than those of the several previously reported XP3 monolayers and demonstrates a significant difference between the electron and the hole carrier mobilities. Strain engineering can significantly affect both the bandgap and optical absorption. These findings indicate that the MgP3 monolayer could have potential applications of optoelectronic, photovoltaic, and photocatalytic materials or devices.