Prediction of 2D Li2X (X=Se, Te) monolayer semiconductors by first principles calculations

Two dimensional monolayer materials play important roles in new generation of electronic and optical devices in nano scale. In this paper, by using first principles calculations, the existence of 2D Li2X (X=Se, Te) monolayer materials are theoretically predicted. Through cohesive energy calculation and phonon dispersion simulation, it is proved that the proposed 2D Li2Se and Li2Te monolayer materials are energetically and dynamically stable suggests their potential experimental realization. Our study shows that these newly predicted compounds are direct semiconductors and have strain tunable wide band gaps. As direct semiconductors, these new monolayers may have many applications in electronics and optoelectronics devices. (C) 2019 Elsevier B.V. All rights reserved.