Magnetic mechanism investigations on the ferromagnetism of (Sr,Na)(Zn,Mn)As with decoupled charge and spin doping

Abstract

AbstractThe electronic structure and the magnetic properties of a new diluted magnetic semiconductor have been investigated, using first‐principles calculations within the Perdew–Burke–Ernzerhof generalized gradient approximation. Compound is a ‐type structure semiconductor with a direct bandgap of 0.57 eV at the point. With spins doped via isovalent (Zn, Mn) substitutions, the system prefers the antiferromagnetic ground state, resulting from the Mn–Mn superexchange interactions. Via off‐stoichiometry (Sr, Na) substitutions, holes are introduced into the system, resulting in the ferromagnetic spin responses for Mn–Mn pairs, except for the nearest‐neighboring Mn–Mn pair. Based on our calculations, the ferromagnetism in the II–II–V‐based diluted magnetic semiconductor originates from Zener's p–d exchange interactions between localized Mn spins and itinerant holes mediated by As atoms.