Interlayer ferromagnetic coupling in nonmagnetic elements doped CrI₃ thin films

The exploration of magnetism in two-dimensional layered materials has attracted extensive research interest. For the monoclinic phase CrI₃ with interlayer antiferromagnetism, finding a static and robust way of realizing the intrinsic interlayer ferromagnetic coupling is desirable. In this work, we study the electronic structure and magnetic properties of the nonmagnetic element (e.g., O, S, Se, N, P, As, and C) doped bi-and triple-layer CrI₃ systems via first-principles calculations. Our results demonstrate that O, P, S, As, and Se doped CrI₃ bilayer can realize interlayer ferromagnetism. Further analysis shows that the interlayer ferromagnetic coupling in the doped few-layer CrI₃ is closely related to the formation of localized spinpolarized state around the doped elements. Further study presents that, for As-doped tri-layer CrI₃, it can realize interlayer ferromagnetic coupling. This work proves that nonmagnetic element doping can realize the interlayer ferromagnetically-coupled few-layer CrI₃ while maintaining its semiconducting characteristics without introducing additional carriers.