Controlling Magnetism in the 2D van der Waals Antiferromagnet CrPS4 via Ion Intercalation.

Two-dimensional (2D) van der Waals (vdW) magnetic materials are platforms in which inserting chemical species into their interlayer gaps offers a powerful route to engineer magnetism. Here, we focus on the A-type antiferromagnetic semiconductor CrPS4 (TN = 38 K) and investigate its electronic and magnetic properties upon intercalation of lithium (Li+) and organic tetrabutylammonium (TBA+) ions using first-principles calculations. Li+ incorporation induces a semiconductor-to-metal transition in CrPS4 and triggers a switching from an out-of-plane antiferromagnetism state to an in-plane ferromagnetic state. This is accompanied by an increase of the ordering temperature, reaching a 5-fold enhancement for Li0.5CrPS4. TBA+ intercalation expands the vdW gap, decoupling CrPS4 layers and stabilizing in-plane ferromagnetism with TC > 100 K. Furthermore, it enhances magnon group velocities and yields more isotropic magnon transport. This work highlights intercalation as a powerful approach for tailoring magnetism, paving the way for tunable 2D-layered magnetic materials for spintronic and magnonic applications.