First-principles investigations on the structural stability, thermophysical and half-metallic properties of the half-Heusler CrMnS alloy

Half-Heusler alloys are anticipated to impact real applications for instance industrial waste heat recovery due to their high thermoelectric (TE) properties, good thermal stability, and excellent elastic properties. The state-of-the-art density functional theory (DFT) is used to calculate the electronic structure, magnetic, elastic, thermodynamic, and transport properties of the cubic CrMnS half-Heusler (HH) alloy. Ferromagnetic (FM) configuration is found to be energetically most favorable than non-magnetic (NM) and antiferromagnetic (AFM) states for the HH CrMnS alloy. The spin‐resolved band structure of HH CrMnS prevails its half‐metallicity at the Fermi level with a total magnetic moment of 1 μ_B. The cohesive and formation energy analysis along with the phonon dispersion curve indicate that HH CrMnS is a chemically, thermodynamically, and vibrationally stable compound. Elastic properties for the studied compound show its mechanical stability, anisotropic & brittle nature with high hardness, and Debye temperature of 410 K. Thermodynamic parameters are also calculated which depict the stability of the studied alloy at varied pressure and temperature. Furthermore, thermoelectric (TE) properties indicate that HH CrMnS alloy has a maximum value of power factor (PF) equal to 3.3 × 10¹¹ WK⁻² m⁻¹ s⁻¹ at 1000 K and ZT value of 0.72 at 600 K. The vibrational and mechanical stability, higher bandgap (~ 0.96 eV) and 100% spin-polarization demonstrate that HH CrMnS can be a potential alloy for TE and spintronic applications.