Effect of dopants on the structural, optoelectronic and magnetic properties of pristine AgGaO₃ perovskite: A first principles study

The structural, electronic and optical properties of pristine AgGaO₃ and doped Ag_1-xCr_xGaO₃ (x = 0.25, 0.50 and 0.75 at%) have been explored using first principle simulation based on density functional theory (DFT). The Perdew-Burke-Ernzerhof – Generalized Gradient Approximation (PBE-GGA) is used to optimize the geometry of pristine and Cr doped AgGaO₃ systems. Structural analysis demonstrates that the calculated lattice parameters and unit cell volume decrease with the increase of Cr concentration. The incorporation of Cr at Ag sites significantly affects the electronic band gap of AgGaO₃. All materials are found to be semiconductor with direct band gap values of 1.42 eV, 1.26 eV, 0.65 eV and 0.37 eV for pristine AgGaO₃ and Cr doped Ag_1−xCr_xGaO₃ (at x = 0.25, 0.50, 0.75 at%), respectively. The localized energy states of 75% Cr doped AgGaO₃ play significant role to enhance optical conductivity. Further, Penn's model is confirmed by observing the inverse relationship between the dielectric function and electronic band gap. The significant variations noted in electronic band gap as well as optical characteristics caused by the doping of Cr declares that the doped materials are more appropriate candidates for solar cell and optoelectronic like applications as compared to pristine AgGaO₃. It is further established that magnetism is induced in all Cr doped perovskites. The net magnetic moment computed for each Cr atom is 3 μ_B. All doped systems are found to be ferromagnetic in nature.