Investigation of structural properties and density of states of the cubic phase of Sr2NiWO6

Sr2NiWO6 is number of double perovskites, and have the general formula A2BB O6 [1]. In this paper, we investigate the structural properties and density of state of the cubic phase of Sr2NiWO6. The calculations have been performed using the Full-potential-linearized argumented plane wave(FP-LAPW) method in the framework of perturbation density functional theory whit GGA+U approximation by Wien2k package [2,3]. The lattice constants used in the calculations are a=b=c=7.9346(A0) for cubic phase. In calculations, the convergence parameter, RMTKmax, which control the size of the basis sets in these calculations, was set to 7.0. All these values have been chosen so as to ensure the total energy converged to better than 0.0001 Ry. The cut-off energy, which defines the separation between the core and valence states, was set to -6.0 Ry. The result of density of state show that the spin up and spin down have gap 2.73 Ev[4].Also, we calculated electron density of states in (100) plane for this phase of Sr2NiWO6 and good agreement was obtained compared to the other results. The calculated electron density shows that charge density lines are almost spherical in structure that is sign of existence ionic bond between Sr and O atoms and W and O, Ni-Sr and Sr-W covalent interaction.