AB INITIO EXPLORATION OF STRUCTURAL STABILITY ACROSS PEROVSKITE COMPOUNDS WITH THERMOELECTRIC APPLICATIONS

Abstract

Lead-free perovskite oxides are exceptionally promising thermoelectric materials due to their naturally low thermal conduction and electronically tunable nature. In this work, we report a computational study of the thermoelectric performance of LiGeCl₃ and CuLuO₃, which both have the cubic Pm-3m (#221) space group. Using density functional theory (DFT) combined with Boltzmann transport theory, we compute the critical performance parameters like the Seebeck coefficient, power factor, and dimensionless figure of merit (ZT). LiGeCl₃ has a direct band gap energy of 1.01 eV and CuLuO₃ has an indirect band gap energy of 1.86 eV, and both have very good electronic transport properties. At the same time, large-scale stability analysis of various other perovskite compounds are reviewed by phonon dispersion analysis, Goldschmidt tolerance factor calculation, and structural response calculation against temperature change showing the uncertainty in stability result. The review also examines lattice anharmonicity at low temperatures to understand its contribution to thermal conductivity. This study stresses the thermoelectric potential of LiGeCl₃ and CuLuO₃, while also presenting a framework for the identification and development of perovskite-based thermoelectric materials with both structural stability and high performance.