Electronic structure and half-metallic property of Si_3CaC_4

摘要

The electronic structures and magnetic properties of Si_3CaC_4 in zinc-blende phase has been studied by employing the first-principles method based on density functional theory (DFT). The calculations predict stable ferromagnetic ground state in Si_3CaC_4, resulting from calcium substitution for silicon. The calculated total magnetic moment is 2.00 μ_B per supercell, which mainly arises from the Ca and neighboring C atoms. Band structures and density of states studies show half-metallic (HM) ferromagnetic property for Si_3CaC_4. The ferromagnetic coupling is generally observed between the Ca and C atoms. The ferromagnetism of Si_3CaC_4 can be explained by the hole-mediated double exchange mechanism. The sensitivity of half-metallicity of Si_3CaC_4 as a function of lattice constant is also discussed, and the half-metallicity can be kept in a wider lattice constant range.