Theoretical prediction and property evaluation of new two-dimensional materials: BeN4C8 and MgN4C8 sheets

Abstract

In the present study, new two-dimensional materials, denoted as BeN₄C₈ and MgN₄C₈ sheets, are predicted by density functional theory. This research focuses on the structural stability of these sheets by examining cohesive energy and phonon dispersion. The findings indicate that both BeN₄C₈ and MgN₄C₈ sheets demonstrate structural stability, evidenced by their negative cohesive energies and no imaginary frequencies in their phonon spectra. Herein, the thermal stability of these sheets is confirmed at temperatures beyond room temperature. We have also investigated the mechanical characteristics, calculating Young's modulus along with Poisson's ratio to understand their anisotropic behavior. The results reveal that BeN₄C₈ and MgN₄C₈ sheets can be the suitable candidates for applications in nanomechanics, especially when softer materials than graphene are required. The electronic properties of both materials are examined, highlighting their metallic characteristics. The study also delves into the optical properties of BeN₄C₈ and MgN₄C₈, studying their dielectric function, absorption coefficient, optical conductivity, and reflection coefficient across a range of photon energies. The results highlight significant enhancement in the optical response of the electromagnetic spectrum, suggesting that these materials have promising potential for applications in optoelectronic devices and energy harvesting technologies.