Structural, Electronic, Elastic, and Thermoelectric Properties of Eco‐Friendly A 2 ZrNiO 6 (A = Sr, Ba) Doubled Perovskites via Ab‐Initio Approach

Abstract

In the present investigation, Sr 2 ZrNiO 6 and Ba 2 ZrNiO 6 were examined using full‐potential augmented plane wave (FP‐APW) method based on density functional theory, with particular emphasis on their structural, electronic, mechanical, and thermoelectric characteristics. The equilibrium structural parameters were obtained by optimizing crystal geometry within the PBE–GGA formalism. For a more accurate description of electronic structure, the GGA+U method was combined with the Tran–Blaha modified Becke–Johnson (TB‐mBJ) potential, while spin–orbit coupling (SOC) was also taken into consideration. The charge‐transport behavior was subsequently investigated through semiclassical Boltzmann transport calculations using constant relaxation‐time approximation. Stability was assessed from the formation energies, elastic parameters, and phonon spectra of the optimized structures, all of which support the thermodynamic, mechanical, and dynamical stability of both compounds. Electronic structure calculations reveal indirect semiconducting band gaps of 0.72 eV for Sr 2 ZrNiO 6 and 1.00 eV for Ba 2 ZrNiO 6 . The maximum undoped ZT values are 0.0239 at 300 K for Sr 2 ZrNiO 6 and 0.3251 at 700 K for Ba 2 ZrNiO 6 . The findings of this study provide useful theoretical insight for the design and optimization of oxide‐based thermoelectric materials. Among the two compounds, Sr 2 ZrNiO 6 exhibits a more favorable response to carrier concentration optimization, making it a promising candidate for high‐temperature thermoelectric applications.