First-principles investigation of structural, elastic, and mechanical stability of CdxMg1-xO alloys

Magnesium and cadmium oxides (MgO, CdO) are widely used in optoelectronic technology, and CdxMg1-xO oxides exhibit an interesting band gap. For this reason, they are a significant subject of research. In this work, the structural and elastic properties of rock-salt CdxMg1-xO were investigated using two exchange-correlation functionals (LDA and GGA-WC). The calculations were performed using the Full-Potential Linearized Augmented Plane Wave (FP-LAPW) method within the framework of Density Functional Theory (DFT). The lattice parameter was Calculated for various cadmium concentrations (x) in the rock-salt structure, showing a quasi-linear variation from 4.257 A° for MgO to 4.43 A° for CdO. With deviations of less than 1%, the calculated values was in good agreement with experimental data for both rs-MgO and rs-CdO. In addition, the three independent elastic constants were computed, together with associated parameters including bulk modulus, shear modulus, and Young's modulus for CdxMg1-xO in the rock-salt structure. The quasi-linear change in the elastic characteristics is also evident, with the values of C11, C12, and C44 for rs-MgO changing from 334.85, 94.84, and 98.28 to 242.88, 124, and 48.08 for rs-CdO, respectively.