Enhanced mechanical, optoelectronic and thermoelectric properties of binary CdO by under pressure: An ab initio study

This manuscript presents, under the effect of different pressures (0–60 GPa), the structural, mechanical, electronic, optical, and thermoelectric properties of CdO with NaCl type structure by using the FP-LAPW (Full Potential Linearized Augmented Plane Wave method) with Generalized Gradient Approximation (GGA) whose basis is the Density Functional Theory (DFT). PBE-GGA was used to compute the structural, elastic, optical, electronic, and thermoelectric properties using Tran-Blaha modified Becke-Johnson (TB-mBJ) potential. Different terms like formation energy, cohesive energy, and phonon were used for the computation of thermal stability and that is further confirmed by elastic properties. Bulk moduli and pressure-dependent lattice constants were achieved by using the optimization method. From the results, we can say that the increase in pressure is directly related to the band gap and inversely related to the lattice constant. The mechanical properties show that CdO is highly ductile and mechanically stable and ductility is directly related to pressure. The minimum conduction band goes to a higher energy level when the pressure increases while the maximum valance band goes to a lower energy level ultimately the energy band gap increases. The optical parameter curve does not change by increasing pressure but the peaks start moving towards the higher energies slightly. Calculations reveals that band gap increases by increasing pressure which shows the blue shift in optical properties. The optical properties spectrum was studied, including reflectance, dielectric coefficient, and absorption coefficient. The optical constants show that the phase of CdO with NaCl structure was translucent. In the end, the thermoelectric feature in terms of thermal conductivity (K), power factor (PF), Seebeck coefficient (S), and electrical conductivity (σ) were studied by using the BoltzTrap code as a function of temperature. Thermoelectric and optical aspects revealed that pressure induces the possible use of CdO material for various TE and optical applications.