Magnetoelectronic and optical properties of CoMnZnSi quaternary Heusler alloy

The structural stability, fully spin-polarized electronic structure, and optical properties of CoMnZnSi quaternary Heusler alloy in the bulk form as well as (111)-slab have been investigated on the basis of the density functional theory (DFT). Formation energy, cohesive energy, and elastic constants confirmed that the bulk CoMnZnSi is thermodynamically and mechanically stable at an optimized lattice parameter of 5.81 Å. The atomic relaxation and surface energies are predicted for the (111)-slab of the CoMnZnSi alloy. The results indicate that the Co (111), Mn (111), Zn (111), and Si (111)-slabs are thermodynamically stable. The bulk CoMnZnSi has shown a perfect half-metallic behavior with an integer value of magnetic moment (4 µ_B) and unexpectedly large spin-flip gap of 0.39 eV, while Co (111) and Si (111)-slabs have shown semi-metallic nature at the Fermi level. Therefore, this Heusler alloy can be a promising candidate material for spintronic applications. Optical properties, including conductivity, dielectric functions, reflectivity, absorption, refractive index, and loss function, are investigated from the complex dielectric function relation.