Double half-Heusler Compounds: Novel High Efficiency Thermoelectric Materials for Energy Applications

Abstract

This dissertation presents a theoretical investigation of three titanium-based double half-Heusler compounds: Ti2OsNiSb2, Ti2OsPtSb2, and Ti2OsPdSb2, using first-principles DFT calculations via Quantum ESPRESSO packadge. The optimized lattice parameters confirm a stable tetragonal structure with c/a ratio ≈ 2.00, indicating minimal distortion compared to the cubic half-Heusler phase. The calculated lattice constants are respectively: 6.086إ for Ti2OsNiSb2; 6.207إ for Ti2OsPtSb2; and 6.194إ for Ti2OsPdSb2. with negative formation energies confirming structural stability