First-principles exploration of sp-electron digital magnetic heterostructures: The case for CaO δ-doped with 2p-block elements boron, carbon, and nitrogen

Abstract Most previous studies on digital magnetic heterostructures have been concerned with materials containing d -block and f -block magnetic ions. In this work, we predicted several alkaline-earth monoxide-based digital magnetic heterostructures via anionic substitution by main group elements, exhibiting sp -electron ferromagnetism. First-principles calculations were performed to investigate rock-salt CaO δ -doped with 2 p -block elements B, C, and N atoms. Semiconducting and half-metallic ferromagnetic states were found and identified. Spin polarization was mainly derived from the 2 p holes induced by substitution, i.e., replacing oxygen with boron, carbon, and nitrogen. The orbital-specific spin-polarized states were characterized and the relationships between the electronic structures and magnetic properties were described and explained. Moreover, the carriers were mostly concentrated within a narrowly confined area around the δ -doped layers, and were for the most part not acted on the host layers, showing a spin polarization of the two-dimensional hole gas.