STRUCTURAL, ELECTRONIC AND OPTICAL PROPERTIES OF MgSxSe1-x, MgSxTe1-x AND MgSexTe1-x (0 ≤x ≤1) ALLOYS FROM FIRST PRINCIPLES

First principles total energy calculations have been performed using full potential linear augmented plane wave method (FP-LAPW) within density functional theory to study the structural, electronic and optical properties of MgSxSe1-x, MgSxTe1-x and MgSexTe1-x alloys in the rock salt crystallographic phase. The generalized gradient approximation parameterization scheme has been used for calculating the ground state structural parameters and their deviation from the Vegard's law has been discussed. Full relativistic electronic band structures and density of states have been calculated to study the electronic properties of the end binary compounds and ternary alloys MgSxSe1-x, MgSxTe1-x and MgSexTe1-x (0.25 < x < 0.75). Optical bowing for these semiconductor alloys has been discussed in term of volume deformation, electronegativity and structural relaxation. Optical properties of the binary and ternary magnesium chalcogenides have been calculated in terms of the complex dielectric function and the results are compared with available theoretical and experimental data.