Interlayer Coupling In Intrinsically Magnetic Bilayer Sco2 And Nbn2

Two-dimensional (2D) van der Waals (vdW) intrinsic magnets have been used to fabricate spin filter magnetic tunnel junctions and spin tunnel field-effect transistors, and the interlayer coupling of 2D vdW intrinsic magnets is of vital importance for obtaining high performance vdW spintronic devices based on 2D materials. In this work, we investigate the electronic structures and magnetic properties of bilayer ScO2 and NbN2 by using first principles calculations. It is found that AB stacking is the most preferred stacking order of bilayer ScO2 and NbN2. Furthermore, the ground state of AB-stacked bilayer ScO2 is a semiconductor with intralayer ferromagnetic (FM) and interlayer antiferromagnetic (AFM) couplings, and the magnetic moments are mainly provided by the p(z) orbits of the O atoms. In contrast, the ground state of AB-stacked bilayer NbN2 is a metal with intra- and inter-layer FM couplings, and the magnetic moments are mainly from the d(z)(2) orbits of the Nb atoms. In particular, the interlayer AFM coupling of AB-stacked bilayer ScO2 is much larger than intralayer FM coupling due to the superposition of the spin-polarized p(z) orbits of the O atoms in adjacent layers. Compared to the strong interlayer AFM coupling of bilayer ScO2, the interlayer magnetic coupling of AB-stacked bilayer NbN2 is negligible because the spin-polarized d(z)(2) orbits of the Nb atoms in adjacent layers do not overlap. Our results will benefit a deep understanding of the interlayer coupling of 2D vdW intrinsic magnets and exploring of high performance spintronic devices based on 2D vdW intrinsic magnets.