Magnetic interactions in a proposed diluted magnetic semiconductor (Ba$_\text{1-x}$K$_\text{x}$)(Zn$_\text{1-y}$Mn$_\text{y}$)$_\text{2}$P$_\text{2}$

Abstract

By using first-principles electronic structure calculations, we have studied the magnetic interactions in a proposed BaZn2P2-based diluted magnetic semiconductor (DMS). For a typical compound Ba(Zn0.944Mn0.056)2P2 with only spin doping, due to the superexchange interaction between Mn atoms and the lack of itinerant carriers, the short-range antiferromagnetic coupling dominates. Partially substituting K atoms for Ba atoms, which introduces itinerant hole carriers into the p orbitals of P atoms so as to link distant Mn moments with the spin-polarized hole carriers via the p-d hybridization between P and Mn atoms, is very crucial for the appearance of ferromagnetism in the compound. Furthermore, applying hydrostatic pressure first enhances and then decreases the ferromagnetic coupling in (Ba0.75K0.25)(Zn0.944Mn0.056)2P2 at a turning point around 15 GPa, which results from the combined effects of the pressure-induced variations of electron delocalization and p-d hybridization. Compared with the BaZn2As2-based DMS, the substitution of P for As can modulate the magnetic coupling effectively. Both the results for BaZn2P2-based and BaZn2As2based DMSs demonstrate that the robust antiferromagnetic (AFM) coupling between the nearest Mn-Mn pairs bridged by anions is harmful to improving the performance of this II-II-V based DMS materials.