First-principles calculations of structural properties and lattice dynamics in ZnSexTe1−x alloys

We report ab initio calculations of the structural properties and lattice dynamics of ZnSexTe1−x. The structural, dielectric and dynamical properties were determined for the bulk materials (ZnSe and ZnTe). To study the alloy-disorder, special quasi-random structures are used, where the Se and Te atoms are randomly positioned and controlled by the pair correlation functions. The variation of lattice parameter, bonds length and radial distribution function, are calculated using a plane wave pseudopotential method within the density functional theory. A linear response approach is used to derive phonons spectra. The results are in good agreement with extended X-ray absorption fine structure (EXAFS) and Raman spectra.