Tailoring the electronic and magnetic properties of AA-stacked ZnO bilayer by engineering covalently bonded F/N-intercalation or introducing SiC substrate

Abstract

To meet the current requirements for diluted magnetic semiconductors, it is essential to design the materials with high stability and spin polarization for promoting the development of spintronic devices. Amelioration on the properties of two-dimensional ZnO bilayers for high-performance optoelectronic and spintronic remains a significant challenge and is highly anticipated. Herein, we systematically investigated the electronic structures and magnetic properties of AA-stacked ZnO bilayers through the first-principles calculations, focusing on the effects of covalently bonded F/N-intercalation and the introduction of SiC substrate. The results indicate that pristine ZnO BL, F@ZnO, N@ZnO bilayer and ZnO/SiC heterostructure exhibit dynamical, and mechanical and thermal stability. F@ZnO and N@ZnO exhibit magnetic properties, and the magnetic moments are 0.659 μ_B and 1.0 μ_B, which are primarily derived from O-2p and N-2p orbitals, respectively. F@ZnO exhibits half-metallic magnetic characteristics, whereas N@ZnO displays metallic features at high intercalation concentrations up to 100%. The stable half-metallicity originates from a spontaneous phase transition driven by Stoner instability due to the high density of states peak near the Fermi level. In ZnO/SiC heterostructure, one of the ZnO layers adjacent to the SiC layer becomes buckled with a height of 0.891 Å, while the other ZnO layer, situated farther from the SiC layer, remains planar. Furthermore, the system undergoes the transition from a nonmagnetic state to a ferromagnetic state due to the introduction of C atoms. These findings provide a new platform for designing 2D magnetic thin films, which could hold potential for enhancing the application of ZnO materials in optoelectronic and spintronic devices.