First principle calculation of electronic structures and optical properties of copper and nickel doped FeS2
(School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China)
Abstract: The crystal and electronic structures, optical properties of copper and nickel mono- and co-doped FeS2 were studied by the ？rst-principles plane-wave ultrasoft pseudopotential method with the generalized gradient approximation. The results show that, the lattice deformation of FeS2 occurs and the lattice parameters increase after doping. And the impurity energy level is introduced by Cu and Ni doping, which also leads to decrease of the band gap of FeS2. Fermi levels moves upward and into conduction band and density of states traverses the Fermi level, indicating that the doped FeS2 is degenerate semiconductor which shows stronger metallic characteristic and electrical conductivity. In addition, the doping results in peaks redshift and amplitudes decrease of imaginary part of dielectric function, absorption coefficient and conductivity. Optical transition is significantly enhanced and so are absorption coefficient and conductivity within visible region in the co-doping system. The photoabsorption capacity and photoelectrical efficiency of FeS2 are highly strengthened in Cu-Ni co-doping system.
Key words: Cu-Ni doping; FeS2; optical property; ？rst-principles calculation