Half metallicity and magnetic stability of sp-electron superlattices in rock-salt structure: A first-principles study

•The magnetic behavior of rock-salt sulfide superlattices in the (001) direction is investigated.•All these superlattices maintain the half metallicity.•The p–p hybridization is shown to be essential for the formation of spin polarization.•S atoms in different layers of the superlattices show distinct polarized directions.•Discussion of volume-conserving deformations further demonstrates the magnetic stability.

Density functional calculations were performed to study the structural, electronic, and magnetic properties of sp-electron half-metallic superlattices (KS)1/(CaS)1, (RbS)1/(SrS)1, and (CsS)1/(BaS)1 (001) in rock-salt structure. All the superlattices are found to be spin polarized, and the calculated band structure suggests a 100% polarization of the conduction carriers. The p–p hybridization is shown to be essential for the formations of localized orbitals and spin-splitting. The half-metallic electronic structure will be destroyed upon an excessive lattice compression, accompanying with a metallic transition. Moreover, the analysis of the orbital-decomposed partial density of states and spin density reveal that S atoms in different layers of the superlattice show distinct polarization directions. Discussion of volume-conserving deformations further demonstrates the stability of half metallicity in sp-electron superlattices.