DFT-based Prediction of promising structural, elastic and Thermoelectronic properties in BaAgX3 (X= I, Br, and Cl) halide perovskites

The aim of this research is to explore the structural, electronic, elastic, mechanical and thermoelectric properties of inorganic halide perovskites BaAgX3 (X = I, Br, and Cl) through theoretical calculations guided by Density Functional Theory (DFT). We performed our computations using full potential linearized augmented plane wave (FP-LAPW) method, combined with the generalized gradient approximation (GGA-PBE) and Tran-Blaha modified Beck-Johnson (TB-mBJ) approximations to model the exchange-correlation potential as generated by the Wien2k code. The structural parameters, such as the lattice constant were calculated and found to be in excellent agreement with existing theoretical results, and the formation energy evaluation verifies the chemical stability of the compounds. Electronic properties derived from band structure and density of states for all compounds show a semiconducting behavior with an indirect band gap. Electron density mapping identifies covalent bonding in (Ag-X) and ionic bonding in (Ba-X). The elastic and mechanical properties were also computed, revealing that the compounds concerned are mechanically stable following Born stability criteria and exhibit both ductility and anisotropic character. Finally, the thermoelectric properties of halide perovskites were investigated using the BoltzTraP code. The analysis focused on key parameters like Seebeck coefficient, electrical conductivity, power factor, and figure of merit (ZT) across a temperature range of 300-1200 K. The results highlight the promising potential of these materials for both optoelectronic and thermoelectric applications due to their semiconductor and thermoelectric properties.