Na and Cr co-doped BaCd2As2: A hexagonal structured diluted magnetic semiconductor with decoupled charge and spin doping

The electronic structures and magnetic properties of Na-doped, Cr-doped and (Na, Cr) co-doped BaCd₂As₂ by using first principle calculations. The pure BaCd₂As₂ shows a non-magnetic semiconductor with a bandgap about 0.5 eV. The Na-doped BaCd₂As₂ is still non-magnetic semiconductor, and the valence band exist a slight upward shift due to the increase of carries by introducing Na dopant. The doping of Cr atom leads to the magnetic generation of the pure BaCd₂As₂, which mainly comes from the Cr-3d orbitals, but the anti-ferromagnetic state of most systems plays a leading role. And the (Na, Cr) co-doped system with decoupled charge and spin doping prefers ferromagnetic state to be the ground state, and the origin of magnetism can be explained by p-d hybridization, which is due to the coupling interaction between Cr-3d and As-5p.