Ab initio electronic structure of NiCoCrGa half-metallic quaternary Heusler compound

In this study, ab initio calculation results of electronic structure and elastic properties of NiCoCrGa quaternary Heusler compound are presented. Plane wave pseudopotential method is used with spin-polarized Generalized Gradient Approximation (σ-GGA) scheme of the Density Functional Theory (DFT). Static elastic constants of the cubic system satisfy mechanical stability criteria. The cubic phase of the system remains stable under tetragonal distortion. The spin-polarized electronic band structures and density of electronic states indicate a metallic band structure for majority spins, while minority spin structure has semiconducting character. This situation displays a slightly disturbed half-metallic behavior with high-spin polarization ratio (P = 0.961) at Fermi level EF. Two electronic bands of minority spins resulting from d-states of cobalt atom cross Fermi level at Γ-point. This situation gives a finite but very low density of states at EF. The material can be classified as a new half-metallic ferromagnet for spintronic applications.

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► NiCoCrGa system displays half-metallic character with high spin polarization ratio (R = 0.961).
► Total magnetic moment of the system is 4.01 μB which scales with the number of valence electrons.
► Magnetic moment of the system is largely localized on chromium site.
► Cubic phase remains stable under tetragonal distortion.