Electronic structure and half-metallic property of Si3CaC4

The electronic structures and magnetic properties of Si₃CaC₄ 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 Si₃CaC₄, 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 Si₃CaC₄. The ferromagnetic coupling is generally observed between the Ca and C atoms. The ferromagnetism of Si₃CaC₄ can be explained by the hole-mediated double exchange mechanism. The sensitivity of half-metallicity of Si₃CaC₄ as a function of lattice constant is also discussed, and the half-metallicity can be kept in a wider lattice constant range.