Intercalation induced ferromagnetism in group-V transition metal dichalcogenide bilayer

Two-dimensional (2D) ferromagnetic materials are receiving great attention in recent years. However, owing to strong direct magnetic coupling between different layers, they usually prefer antiferromagnetic coupling between different layers once stacked together. It would be of great interest if one can tune such antiferromagnetism to ferromagnetism, which is preferable for further magnetic information storage, and large magnetic moments can be achieved (proportional to thin-film thickness). In the current work, we theoretically and computationally suggest an effective method to tune the interlayer magnetic coupling between two magnetic materials (VX2, X = S, and Se). We show that intercalating a layer of alkali metals could enhance indirect magnetic exchange, and ferromagnetic interlayer coupling between different VX2 layers can be achieved. Our work provides a new and effective route to control and modulate the magnetic exchange between 2D magnetic materials.