Structural, electronic, thermodynamic and optical properties of alkaline earth oxides MgO, SrO and their alloys

Abstract

The structural, electronic, optical and thermodynamic properties of Mg1−xSrxO ternary alloys in NaCl structures at various Sr concentrations are presented. The calculations were performed using the full potential linearized augmented plane wave (FP-LAPW) method within the density functional theory (DFT) in the local density approximation (LDA) and two developed refinements, namely the generalized gradient approximation (GGA) of Perdew et al (1996 Phys. Rev. Lett. 77 3865) for the structural properties and Engel and Vosko (1993 Phys. Rev. B 47 13164) for the band structure calculations. Deviation of the lattice constants from Vegard's law and the bulk modulus from the linear concentration dependence (LCD) were observed for the alloys. The microscopic origins of the gap bowing were explained by using the approach of Bernard and Zunger (1986 Phys. Rev. Lett. 34 5982). The refractive index and optical dielectric constant for the alloys of interest were calculated by using different models. In addition, the thermodynamic stability of the alloys was investigated by calculating the critical temperatures of alloys.