Ab Initio Study of the Properties of Ti2PdFe(Ru)Sb2 Double Half-Heusler Semiconducting Alloys.

Using ab initio calculations, we studied the structural, mechanical, electronic and thermoelectric properties of the new double half-Heusler alloys, Ti₂PdFeSb₂ and Ti₂PdRuSb₂. Our calculations predict stable non-magnetic semiconducting phases with indirect bandgaps of 0.9 eV for Ti₂PdFeSb₂ and 0.7 eV for Ti₂PdRuSb₂. The calculated formation energies and elastic constants suggest that both alloys are thermodynamically as well as mechanically stable. A detailed thermoelectric response (S, κ_e, PF, ZT) of the alloys was investigated using semi-classical Boltzmann transport theory as implemented in BoltzTraP2 code. The lattice thermal conductivity κ_L was evaluated through the Slack model and shows a maximum value of 9.46Wm⁻¹ K⁻¹ for Ti₂PdFeSb₂ and 7.22Wm⁻¹ K⁻¹ for Ti₂PdFeSb₂, at 900 K. The collected results suggest that both compounds would be potential candidates for thermoelectric applications. [ABSTRACT FROM AUTHOR]