Intercalation Induced Magnetic Modulation in Bilayer CrSe₂

Abstract

The discovery of two-dimensional (2D) magnetism offers an exceptional prospect for the advancement of magnetoelectric nanodevices. This is due to its ability to produce ultra-thin, flexible, and highly efficient materials with distinctive magnetic characteristics that were previously unattainable. Such materials could enable advances in data storage, quantum computing, and sensing technologies by providing improved performance and reduced size compared to conventional bulk magnetic materials. Manipulating magnetism at the atomic level allows for precise control and opens new avenues for unique device designs with novel functionalities. However, the widespread application of 2D magnets is currently limited by the scarcity of materials that exhibit significant magnetic anisotropy and high transition temperatures. In this study, we investigate the impact of atomic intercalation on the magnetic properties of a CrSe2 bilayer using first-principles density functional theory (DFT) calculations. Our results reveal that intercalation significantly stabilises the bilayer and induces a magnetic phase transition from an antiferromagnetic (AFM) to a ferromagnetic (FM) ground state, except for the cases of Na and Be intercalations, in which AFM ordering is retained. Notably, CrSe₂-Be exhibits AFM ordering characterised by ferromagnetic intralayer and antiferromagnetic interlayer coupling. Furthermore, the MAE increases from 0.16 meV/Cr in the pristine bilayer to 0.69 meV/Cr in the CrSe₂-Be, although the system maintains its easy-plane magnetic behaviour. In contrast, intercalation with alkali metals (Li and Na) induces a positive shift in MAE with improved magnetic properties, promoting out-of-plane magnetic orientation. The transition temperature rises from 65 K to 350 K for CrSe2-Be and 200 K for CrSe2-Mg. These findings demonstrate that intercalation is a robust and strategy for engineering highperformance 2D magnets with elevated thermal stability and magnetic anisotropy, providing a potential platform for next-generation spintronic devices.