Structural, electronic, mechanical and phonon properties of half-Heusler GaNiSb, InNiSb and InPdSb alloys via first-principles calculations

In this report, the ground state properties of the half-Heusler GaNiSb, InNiSb and InPdSb alloys in the cubic LiAlSi-type structure, are investigated using the Full Potential Linearized Augmented Plane Wave (FP-LAPW) method as implemented in WIEN2k code, based on Density Functional Theory (DFT). The Perdew–Berke–Ernzerhof (PBE) Generalized Gradient Approximation (GGA) is used for exchange–correlation functional. The calculated formation energies and volume-optimization curves of three different structural configurations (Type 1, Type 2 and Type 3) of these alloys reveal that Type 3 configuration is the most favorable (lowest energy structure) structure. According to the Slater–Pauling rule, the studied alloys are non-magnetic in nature in the stable Type 3 configuration. Therefore, the calculation of ground state properties of these alloys are examined in the Type 3 structural configuration and non-magnetic state. The results of electronic structure and density of states reveal that these alloys are metallic in nature. These alloys are dynamically stable as demonstrated by their calculated phonon dispersion spectra. As the three independent elastic constants C11, C12 and C44 satisfy Born–Huang stability condition, these alloys are stable elastically. The studied alloys are ductile in nature, elastically anisotropic and GaNiSb is found to be stiffer than InNiSb and InPdSb by the calculation of mechanical properties. The present work is in good agreement with the previously reported results.