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

• Magnetism of monolayer CrI 3 can be remarkably tunable by charge doping based on density functional studies. • Li adsorption significantly enhances magnetic anisotropy energy (MAE) of monolayer CrI 3 as predicted by electron doping. • F adsorption may distort CrI 3 , although it can also enhance MAE as hole doping when fixed on the surface. • Li adsorption can also tune the easy axis of CrI 3 from out-plane to in-plane. 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 CrI 3. 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 CrI 3 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 CrI 3 –based materials in spintronic devices. [ABSTRACT FROM AUTHOR]