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 thispaper, 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 planewave(FP-LAPW) method in the framework of perturbation density functional theory whitGGA+U approximation by Wien2k package [2,3]. The lattice constants used in the calculations area=b=c=7.9346(A0) for cubic phase. In calculations, the convergence parameter, RMTKmax, whichcontrol the size of the basis sets in these calculations, was set to 7.0. All these values have beenchosen 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 ofdensity of state show that the spin up and spin down have gap 2.73 Ev[4].Also, we calculatedelectron density of states in (100) plane for this phase of Sr2NiWO6 and good agreement wasobtained compared to the other results. The calculated electron density shows that charge densitylines are almost spherical in structure that is sign of existence ionic bond between Sr and O atomsand W and O, Ni-Sr and Sr-W covalent interaction.

Keywords:

Double Perovskites , Density Functional Theory , Generalized-Gradient Approximation