First-principles study of electronic structure and thermoelectric properties of p-type XIrSb(X = Ti, Zr and Hf) half-Heusler compounds

This work reports First-principle Density Functional Theory(DFT) calculation of structural, electronic, and thermoelectric properties of p-type XIrSb(X = Ti, Zr and Hf) half-Heusler compounds. Generalized Gradient Approximation(GGA) with Perdew-Burke-Ernzerhof parameterization flavour for solids (PBEsol) is used for exchange-correlation potential functional. Spin-orbit coupling(SOC) is included in the calculations. The highest value of electronic fitness function(EFF) at 800 K with SOC are 0.83 x 10(-19) W-5/3 ms(-1/3) K-2, 1.11 x 0(-19) W-5/3 ms(-1/3) K-2 and 1.10 x 0(-19) W-5/3 ms(-1/3) K-2 for TiIrSb, ZrIrSb and HfIrSb respectively. The figure of merit(ZT) obtained at 800 K with SOC are 0.87, 0.95 and 0.90 for TiIrSb, ZrIrSb and HfIrSb respectively. The values EFF and ZT of p-type XIrSb(X = Ti, Zr and Hf) obtained in this work show that these compounds are high-performance thermoelectric materials.