First-principles calculations of electronic, optical and elastic properties of Ba₂MgWO₆ double perovskite

The structural, electronic, optical and elastic properties of the cubic double perovskite Ba₂MgWO₆ were calculated using the ab initio plane wave method and compared with the available experimental data. The pressure effects were modeled by optimizing the crystal lattice structure and calculating the band gap at elevated hydrostatic pressures. The calculated values of the relative change of a unit cell volume with pressure are in excellent agreement with the recent experimental measurements [S. Meenakshi et al, J. Phys. Chem. Solids 72 (2011) 609]. The pressure coefficients of the lattice constant and the WO, MgO, BaO bonds variations were all evaluated. Elastic anisotropic properties were analyzed by calculating all independent components of the elastic constants tensor; the greatest and the smallest values of the Youngs moduli were determined.