Bulk Modulus, Elastic Constants, and Force Constants of Interatomic Bonds of II–III₂–VI₄ Compounds

Ab initio density functional perturbation theory is used to calculate the elastic constants of CdGa 2 S 4 , CdGa 2 Se 4 , CdGa 2 Te 4 , and ZnGa 2 Se 4 thiogallates. The values of the bulk modulus, shear modulus, Young's modulus, and Poisson's ratio are determined. The force constants of interatomic bonds in CdGa 2 Te 4 and ZnGa 2 Se 4 compounds are calculated. Regularities in the dependence of the frequencies of Raman‐active phonons on the atomic masses are established.