Magnetic interactions in a proposed diluted magnetic semiconductor (Ba1-xKx)(Zn1-yMny)2P2

摘要

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 BaZn2As2-based DMSs demonstrate that the robust antiferromagnetic (AFM) coupling between the nearest Mn-Mn pairs bridged by anions is harmful to improving the performance of these Ⅱ-Ⅱ-Ⅴ based DMS materials.