Theoretical study of enhanced ferromagnetism and tunable magnetic anisotropy of monolayer CrI3 by surface adsorption

Magnetic anisotropy energy (MAE) plays a key role for 2D magnetic materials, which have attracted significant attention for their promising applications in spintronic devices. Based on first-principles calculations, we have investigated the influence of surface adsorption on the ferromagnetism and MAE of monolayer CrI₃. We find that Li adsorption can dramatically enhance its ferromagnetism, and tune its easy magnetization axis to the in-plane direction from original out-of-plane at certain coverage of Li. The monotonic enhancement of in-plane magnetism in CrI₃ as the coverage of Li increases are attributed to electrostatic doping induced by charge transfer between Li atoms and I atoms, as supported by the charge doping simulation. The tunable robust magnetic anisotropy may open new promising applications of CrI₃–based materials in spintronic devices.