Half-metallic ferromagnetism in the RbX (X = Sb, Te) compounds with the rock salt and zinc-blende structures: A first-principles calculation

• The RbSb and RbTe compounds are half-metallic ferromagnets.
• Magnetic moments are evaluated to be 2 μB/f.u. for RbSb and 1 μB/f.u. for RbTe.
• The rocksalt structure are found to be more stable than the zinc-blende structure.
• The band gaps are 2.94 and 3.61 eV for the RbSb and RbTe.

The first-principles density functional theory (DFT) calculations have been employed to investigate the electronic structures, magnetic properties and half-metallicity of the RbX (X = Sb, Te) compounds with the rocksalt and zinc-blende structures. The RbSb and RbTe compounds with both structures are half-metallic ferromagnet although these compounds do not include transition metal atoms. The compounds with the rock salt structure are found to be more stable energetically than the compounds with the zinc-blende structure. Magnetic moments, independent of crystal structure, are evaluated to be 2 μB/f.u. for RbSb and 1 μB/f.u. for RbTe. The half-metallic band gaps are 2.94 and 3.61 eV for the RbSb and RbTe compounds with the rock salt structure, respectively, while the RbSb and RbTe compounds with the zinc-blende structure have the half-metallic gaps of 3.00 and 3.25 eV, respectively. The lattice distortion does not affect the half-metallic properties of the RbX (X = Sb, Te) compounds with both structures.