Electronic structure and imaginary dielectric function for 2D GaAs doped with Si amphoteric impurities: A DFT study

Without a doubt, the impact of the discovery of 2D systems such as graphene has led to both theoretical and experimental investigations of a large number of materials such as Silicene, Borene, Arsenene, Phosphorene, just to mention some of the most emblematic ones, but other materials and its heterostructures are also of interest. From this point of view, in this work we present the band structure, density of states as well as the imaginary part of the dielectric function of a 2D GaAs system, by means of a density functional theory implementation. The aim of this study is to investigate the basic physical properties for a freestanding 2D GaAs sheet, as well as the effect of Si substitutional atoms, since it has an amphoteric nature in the GaAs, which means that depending on which atom is substituted, this can be an n- or p-type impurity atom. We report, as expected, that the levels do indeed appear near the conduction band (or valence) if the impurity is n-type (or p-type), respectively. Also the density of states due to the impurity is modified as well as the imaginary part of the dielectric function.