The structural stability, lattice dynamics, electronic, thermophysical, and mechanical properties of the inverse perovskites A ₃ OX: A comparative first‐principles study

Abstract

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 (ΘD) 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.