The structural stability, lattice dynamics, electronic, thermophysical, and mechanical properties of the inverse perovskites A₃OX: A comparative first-principles study

We present a comparative study on the structural, electronic, elastic, and thermoelectric properties of the cubic inverse-perovskites A₃OX (where A = Li, Na, K and X = Cl, Br, I) by density functional theory (DFT). The cohesive, formation, and elastic properties analysis indicates that all studied materials are chemically, thermodynamically, and mechanically stable. Electronic properties reveal that all the inverse A₃OX perovskite are direct bandgap semiconductors except Li₃OCl and Li₃OBr with ionic nature which is confirmed by electron localization function (ELF) analysis. We have also calculated Debye temperature (Θ_D) and Grüneisen parameter (γ) to determine the lattice thermal conductivity for all the A₃OX materials. Furthermore, thermoelectric (TE) properties are explored by calculating the Seebeck coefficient (S), electronic thermal conductivity, power factor (PF), electrical conductivity (σ/τ), lattice thermal conductivity, and ZT value. Our investigated A₃OX inverse-perovskites provide a fertile base that can improve the overall TE performance for TE applications and green energy production.