DFT study of optoelectronic and thermoelectric properties of cubic Ba2ZrMO6 (M = Ce, Ti) double perovskites

The full potential linearized augmented plane wave (FP-LAPW) method is used for the investigation of structural, electronic, optical, and thermoelectric (TE) properties of B site ordered transition metal based Ba2ZrCeO6 and Ba2ZrTiO6 double perovskite (DP) oxides. The calculated enthalpies of formation and Goldschmidt's tolerance factors (tau) reveal that studied DP oxides are thermodynamically stable with cubic geometry. Generalized gradient approximation (GGA) along modified Beck Johnson potential (mBJ) potential revealed the bandgaps (E-g) of 3.25 and 3.50 eV for Ba2ZrCeO6 and Ba2ZrTiO6, correspondingly. Further, density of states (DOS) for both compounds is also examined to get a deeper insight into their electronic properties. Investigation of optical properties evidently reveal the optimal absorption of incident light in UV areas, which signifies the potential of studied oxides for being utilized in UV based optical sensors and various other optoelectronic devices. Moreover, analysis of electrical conductivity (sigma), Seebeck coefficient (S), and thermal conductivity (kappa) shows the ZT values of 0.65 for Ba2ZrCeO6 and 0.76 for Ba2ZrTiO6 at 800 K. The results exhibited that both compounds are suitable for optoelectronic and TE devices.