Dielectric function of graphene based quantum dot under the uniaxial stress A controllable red shift and band gap engineering by the stress process

摘要

The dielectric function of graphene based quantum dot under uniaxial pressure has been studied using the density functional theory (DFT) with local-density approximated (LDA) exchange-correlation functionals. The frequency dependent dielectric function has been obtained and the linear optical properties have been studied. It has been shown that stress results in red shift in which the absorption rate depends on the direction of the polarization and the value of the stress. It has also been shown that the uniaxial stress can remove or decrease the band gap obtained due to the geometrical isolation of the quantum dot.