First-principles study on the electronic structures and magnetic properties of a diluted magnetic semiconductor Ba1-xKx(Zn1-yMny)(2)As-2

摘要

Within Perdew-Burke-Ernzerhof generalized gradient approximation, first-principles calculations were performed to investigate the electronic structures and magnetic properties of II-II-V based DMS (Ba,K)(Zn,Mn)(2)As-2 with holes doped via (Ba2+, K1+) replacements, and spins via isovalent (Zn2+, Mn2+) substitutions. Compound BaZn2As2 is paramagnetic semiconductor with a calculated band gap 0.28 eV. With MneMn pair doped in different distances, Ba(Zn1-yMny)(2)As-2 (y = 0.03125) system shows antifer-romagnetic behaviour caused by the short-range superexchange interactions between localized spins of Mn2+ ions. Holes introduced by K dopants lead to metallic behaviour in (Ba1-xKx)(Zn1-yMny)(2)As-2 system and drive the system toward ferromagnetism. The ferromagnetic coupling in the MneMn pair is attributed to the long-range p-d exchange interactions mediated by itinerant holes. Competition between the antiferromagnetic superexchange and ferromagnetic interaction in the MneMn pair determines the magnetic order of (Ba1-xKx)(Zn1-yMny)(2)As-2 system, and the competition is dependent on both the concentration and distribution of K dopants. (C) 2015 Elsevier Masson SAS. All rights reserved.