First-Principles Study of the Enhanced Magnetic Anisotropy and Transition Temperature in a CrSe₂ Monolayer via Hydrogenation

The realization of two-dimensional (2D) magnetism opens an unprecedented possibility for building future magnetoelectric nanodevices; however, wide application is still restricted by the lack of a material platform with a simultaneously large magnetic anisotropy and high transition temperature. To achieve this goal, the modulation of magnetism on currently discovered 2D structures attracts considerable attention. Herein, taking the recently synthesized CrSe2 monolayer as a representative, we investigate the impact of hydrogenation on magnetic and electronic properties via first-principles calculations. The CrSe2 monolayer exhibits high dynamical and thermal stability at a relatively low degree of hydrogenation, and the magnetic ground state transforms from antiferromagnetic to ferromagnetic. Intriguingly, the magnetic anisotropy energy of the CrSe2 monolayer (0.32 meV/Cr) is significantly increased after hydrogenation (up to 0.68 meV/Cr) as well as its Curie temperature. Such an improvement is attributed to the induced interatomic charge redistribution by the adsorption of hydrogen. Our findings reveal that a proper degree of hydrogenation is an effective and nonvolatile strategy for improving the 2D magnetic coupling with great potential for advanced spintronic applications.