Predicting the stable Type-I phase of XMnSb (X= Co, Fe, Os) compounds and its thermodynamic, electronic and magnetic properties from first-principles calculations

Abstract We use Density Functional Theory (DFT) within the Generalized Gradient Approximation (GGA) and Perdew-Burke-Ernzerhof (PBE) exchangecorrelation GGA-PBE functional to predict the structure, magnetic, electronic, mechanical and thermodynamic properties of X M n S b alloys. Both the CoMnSb and FeMnSb compounds are discovered to be ferromagnetichalf-metallic alloys, while the OsMnSb compound is found to be metallic. The elastic constants and moduli revealed these compounds to be mechanically and dynamically stable. From the Pughs and Frantsevichs ratios, both C o M n S b and O s M n S b compounds are ductile materials, while FeMnSb is brittle. In the present calculations, the Zener (Shear) factors predicted both F e M n S b and O s M n S b to be anisotropic, while CoMnSb is isotropic in nature. Although OsMnSb is found to be metallic, the calculated electronic spin-polarized band structure predicted semiconducting CoMnSb and FeMnSb to be half-metallic, with the minority-spin band structures having band gaps of 0.97 and 1.04 eV respectively. Due to a high value of Debye temperature, C o M n S b possesses a stronger covalent bond than both F e M n S b and OsMnSb. Finally, the melting temperature of the compounds is predicted to be 1685.12 ± 300 K, 1535.06 ± 300 K, and 1614.73 ± 300 K in C o M n S b , F e M n S b , and O s M n S b respectively.