Investigation of stability, electronic, optical and mechanical properties of honeycomb BeN2 monolayer: A DFT study

In this work, from the DFT calculations, we investigate the physical properties of the 2D BeN2 monolayer with a honeycomb lattice. The dynamic stability of the BeN2 monolayer is demonstrated by the presence of real modes in its phonon spectrum. The theoretical electronic band structure and density of states reveal the semiconductor nature of the BeN2 sheet. The semi-local PBE results show a bandgap of 1.32 eV, while HSE hybrid functional computation yields a higher bandgap of 3.16 eV. Our results suggest that HSE approximation employing ultrasoft pseudopotentials can accurately predict the most important electronic property of BeN2 structure that is not only in excellent agreement with the most accurate GW predictions but also better than those reported before with the same functional. The wide-bandgap semiconductor properties make BeN2 nanostructure a highly promising 2D material for innovative applications in nanoelectronic devices. The optical analysis obtained from HSE calculations reveals that the BeN2 nanostructure has optical absorption in the violet range of visible light with a low static dielectric constant of 2.55. Further, our results indicate that this material presents low bulk and shear moduli of 61.3 and 12.0 N/m, respectively.