Pursuit of Stability, Electronic, Lattice Dynamics, and Thermoelectric Properties of Half Heusler Compound TiFeSe

Half-Heusler (HH) compounds are increasingly popular for their use as thermoelectricmaterials in high-temperature applications. The present work explores the electronand phonon transport properties of TiFeSe compounds to understand theirthermoelectric behaviour using Density Functional Theory (DFT), semiclassicalBoltzmann transport equation, and Slack's equation. The compound isthermodynamically, dynamically, and mechanically stable, exhibiting non-magneticsemiconductor behaviour with an indirect bandgap of 0.80 eV. The compound has ahigher Young's modulus and bulk modulus, indicating better mechanical strength, andalso has a high melting point, as calculated from the elastic constants. The latticethermal conductivity is 24.84 Wm−1K−1 at room temperature and decreases as thetemperature increases. The maximum power factor (PF) in the compound for holedoping is 182 μW/cmK², leading to a maximum figure of merit (zT) value of 1.45 at1200 K. This study shows that the hole-doped TiFeSe compound is a promisingcandidate for high-temperature power generation in thermoelectric applications.