Electronic structure, magnetic and optical properties of Cr-doped GaAs using hybrid density functional

First-principles calculations based on the HSE hybrid density functional theory has been performed on the electronic structures, magnetic and optical properties of perfect GaAs and Cr-doped GaAs. The optical properties, including the complex dielectric function, optical reflectivity, extinction coefficient, refractive index, absorption coefficient and electron energy loss were discussed for radiation up to 20 eV together with the calculated electronic structure. The results predicate that the system of Cr-doped GaAs exhibits typical half-metallic properties, in which Cr forms deep levels in the forbidden band and reduces the energy gap, increases static dielectric constant, and obviously red-shifts the absorption edge. In addition, a p-d hybridization reduces the magnetic moment of Cr from its free space charge value of 3 mu(B) and a smaller atomic magnetic moments of As and Ga atoms are generated. (C) 2015 Elsevier B.V. All rights reserved.