First-Principles Study of Au-Doping Effects in Hg_(1-x)Cd_xTe (x = 0.25, 0.5, 0.75)

摘要

First-principles calculations based on density functional theory have been performed for the structural and electronic properties of Au-doped mercury cadmium telluride (MCT, Hg_(1-x)Cd_xTe), using the state-of-the-art computational method with the Heyd-Scus-eria-Ernzerh (HSE) of hybrid functional to correct the band gap. Structural relaxations, charge densities, electron localization functions (ELFs), density of states (DOSs) and band structures were obtained to reveal dopant stability and doping efficiency. The bonding characteristics between Au and host atoms were discussed by analysing charge densities and ELFs. The influence of Cd composition on the electronic structure of Au-doped Hg_(1-x)Cd_xTe (x = 0.25, 0.5, 0.75) was also analysed by the calculated DOSs and band structures. It is found that Hg_(0.75)Cd_(0.25)Te and Hg_(0.5)Cd_(0.5)Te are more suitable for the p-type doping than Hg_(0.25)Cd_(0.75)Te. Meanwhile, for both Hg_(1-x)Cd_xTe and Au-doped Hg_(1-x)Cd_xTe, the linear relationships between band gaps and Cd composition are presented.