Electric field-induced band modulation of predicted ternary 2D MXC3 [M:X = As:Ge, Sb:Sn and Bi:Pb] with strong stability and optical properties

Abstract

The present work reports a new series of ternary two-dimensional MXC3 [M:X = As: Ge, Sb: Sn and Bi: Pb] compounds whose stability and existence are confirmed through the phonon dispersion analysis, elastic properties and ab initio molecular dynamics simulation. The developed compounds are further investigated with their electronic and optical properties using density functional theory. We have observed zero bandgap nature in MXC3 compounds, where AsGeC3 shows the graphene-like band structure with Dirac cone at K-point. We have systematically applied the external electric field up to ±0.40 eV/Å to modulate the electronic and optical properties of these compounds. The increasing magnitude of the electric field has shown the increasing nature of bandgap in the AsGeC3 compound, while no effect was observed in case of SbSnC3 and BiPbC3 compounds. Consequently, the bandgap of AsGeC3 compound is tuned up to 0.98 eV which is maximum at an optimum value of the applied electric field of ±0.40 eV/Å. All the three 2D MXC3 compounds have shown the broken symmetry of the structure after the optimum value of the electrical field that can be understood by the maximum tolerance limit of an applied electric field. Our results strongly suggest the excellent mechanical stability of the AsGeC3 compound under the applied electric field. We have also calculated the variation in the optical properties upon the external field for the AsGeC3 compound, which shows a good transparency nature and can be used in the regulation of the smart window applications. We sincerely believe that our outcomes reflect a significant achievement for potential applications in future nanoelectronics and optoelectronic devices along with tunable electronic properties.