First-principle calculations on the electronic structures and magnetic properties of Heusler compounds V_2ReZ (Z=B, Al, Ga, In, Si, Ge, Sn, Sb)

摘要

The electronic structures and magnetic properties of V_2ReZ (Z=B, Al, Ga, In, Si, Ge, Sn, Sb) compounds with CuHg_2Ti-type structure have been investigated. V_2ReZ (Z=A1, Ga, In) compounds are predicted to be half-metallic ferrimagnets at their equilibrium lattice parameter. The half-metallicity can be achieved by expanding the lattice parameter for V_2ReB compound. The half-metallicity still holds when the lattice expansion, contraction or tetragonal deformation occurs for V_2ReZ (Z = B, Al, Ga, In). The energy gap between the e_g and t_(2g) states is the half-metallic gap for V_2ReZ (Z = B, Al, Ga, In) compounds, which causes the compounds to not follow the M_t=Z_t-24 rule but follow an M_r=Z_t-18 rule instead. The influences of lattice change and different Z atoms on half-metallicity and magnetic properties are also discussed.