Electronic structure and magnetism of new scandium-based full Heusler compounds: Sc_2CoZ (Z = Si, Ge, Sn)

摘要

First principles FPLAPW calculations were performed in the framework of Density Functional Theory (DFT), to study the electronic structures and magnetic properties for the new full-Heusler compounds: Sc_2CoZ (Z = Si, Ge, Sn). The investigated materials are stable against decomposition, in ferromagnetic configuration and crystallize in the inverse Heusler structures. The half-metallic properties as function of the variation of unit cell volumes are analysed regarding the fourth main group constituent elements. The electronic structure calculations for Sc_2CoSi and Sc_2CoSn show half-metallic characters, with indirect band gaps of 0.544 eV and 0.408 eV at optimised lattice parameters of 6.28 A and 6.62 A, respectively. For Sc_2CoGe compound, the Fermi energy is not pinned inside the energy band gap from minority density of states, neither for unit cell contraction nor for enlargement. The calculated total magnetic moments are 1μB/f.u., for all compounds, in agreement with Slater-Pauling rule.