Ab initio investigation of the stability, electronic, mechanical, and transport properties of a new double Half-Heusler alloys Ti2Pt2ZSb (Z = Al, Ga, In)

This research investigates the structural, electronic, mechanical, and vibrational properties of double half-Heusler compounds with the generic formula Ti2Pt2ZSb (Z = Al, Ga, and In) using density functional theory calculations. The generalized gradient approximation within the Perdew-Burke-Ernzerhof functional was employed for structural optimization and the hybrid HSE06 functional for electronic properties. Our results demonstrate that these compounds are energetically favorable, dynamically and mechanically stable. Electronic structure calculations reveal that Ti2Pt2AlSb double half-Heusler compound is a non-magnetic semiconductor with an indirect bandgap of 1.49 eV, while Ti2Pt2GaSb and Ti2Pt2InSb are non-magnetic semiconductors with direct bandgaps of 1.40 eV. The alloys exhibit low lattice thermal conductivity (2.35–2.66 W/mK) and high melting temperature (1211–1248 K), making them promising candidates for high-technological applications. Further performed analysis, including phonon dispersion curves, electron localization function (ELF), and Bader charge analysis, provides insights into the bonding character and vibrational properties of these materials.