Electronic structure and half-metallic ferromagnetism in (C, Si, Ge and Sn) doped alkaline-earth sulfides: A first principles approach

• The half-metallic ferromagnetism in alkaline-earth sulfides doped with non-magnetic elements.
• Trends of ground state and magnetic properties for different doping concentrations were studied.
• Magnetic moment induced by np orbitals of dopants.
• Dopants enhance the stability of ferromagnetic state.

The electronic structure and magnetic properties of AeS1−xMx (Ae = Mg, Ca and Sr; M = C, Si, Ge and Sn; x = 0.125, 0.25, 0.50 and 1.00) in the rock salt structure was studied using full potential linear augmented plane wave (FP-LAPW) method within the spin density functional theory. The calculation reveals that the non-magnetic dopants can induce stable ferromagnetic state in alkaline-earth sulfides. Also it is found that the alkaline-earth sulfides exhibit half-metallicity with an integer magnetic moment of 2.00 μB/f.u., with group IV elements as dopants (except for Si, Ge and Sn in MgS). The calculated results show that the minority spin electrons are metallic in nature, while the majority spin electrons show an energy gap around the Fermi level. It also found that the HM gap decreases with the increase of atomic size and concentration of the dopant atoms. The half-metallicity originates from the spin-polarized np like states of dopant atoms in these compounds.