Density-functional theory based structural, mechanical, thermal, electronic, and thermoelectric properties of Zr2XNiSb2 (where X = Fe, Pd, Pt) double half-Heusler alloys

This study investigated the structural, mechanical, thermal, electronic, and thermoelectric properties of double half-Heusler (DHH) alloys Zr2XNiSb2 (X = Fe, Pd, Pt) by density functional theory(DFT). The elasticconstants computation suggested that compounds possess mechanical stability. Moreover, estimated elastic constants have been used to compute additional mechanical parameters. The band gap analysis revealed that Zr2FeNiSb2 is identified as a semiconductor with an indirect band gap of 0.462 eV. However, Zr2PdNiSb2 and Zr2PtNiSb2 exhibited metallic characteristics, as indicated by pseudo gaps of 0.511 eV and 0.517 eV, respectively. The higher values of Debey temperature from 262.02 to 396.9 K indicated that compounds were more stable at elevated temperatures. Moreover, higher values of the thermal power factor (PF) up to4.97 x 10 11 W/mK2s and electrical conductivity 1.64 x 1020 S/ms at 1160 K suggested that compounds could be used as promising candidates for thermoelectric materials.