First-principles investigation of the electronic structure and magnetism of Heusler alloys CoMnSb and Co2MnSb

The spin-polarized electronic band structures, density of states (DOS), and magnetic properties of Co-Mn-based Heusler alloys CoMnSb and Co2MnSb have been studied by first-principles method. The calculations were performed by using the full-potential linearized augmented plane wave (FP-LAPW) within the spin-polarized density functional theory and generalized gradient approximation (GGA). Calculated electronic band structures and the density of states are discussed in terms of the contribution of Co 3d74s2, Mn 3d54s2, and Sb 5s25p3 partial density of states and the spin magnetic moments were also calculated. The results reveal that both CoMnSb and Co2MnSb have stable ferromagnetic ground state. They are ideal half-metallic (HM) ferromagnet at their equilibrium lattice constants. The calculated total spin magnetic moments are 3μB for CoMnSb and 6μB for Co2MnSb per unit cell, which agree with the Slater-Pauling rule quite well.