A multiferroic coupling mechanism in the polar interface region of GaN-ZnO heterojunction: A first-principle study

In this paper, the electronic structure and ferroelectric-ferromagnetic coupling properties of Y-doped and vacancy-containing GaN-ZnO heterojunctions are systematically investigated by using the generalized gradient approximation + U (GGA + U) method within the framework of density functional theory. The results reveal that in systems with vacancy defects, the magnetism is generated by the spin polarization of unpaired electrons induced by cationic vacancies, and the magnetic moment of the system is related to the number of unpaired electrons. However, in systems containing interstitial Y-doping, the s-state and d-state electrons of the Y-doped elements are coupled by orbital hybridization to form bound magnetic polarons. Compared with the system containing vacancies, the bound magnetic polaron systems have better stability, although the magnetic moments are relatively small and the total magnetic moment is limited by the concentration of bound magnetic polarons. And the modulation of different magnetic changes can be achieved in different polar interfaces by adjusting the electric polarization intensity of the bound magnetic polaron systems.