Magnetism in two-dimensional CoX₂ (X = S, Se, and Te), from monolayer to bulk layered structures

We investigate spin-polarized electronic structures of CoX 2 (X = S, Se, and Te) monolayers using the density functional theory. We find that CoS 2 and CoSe 2 monolayers are metallic ferromagnetic materials, whereas CoTe 2 monolayer is nonmagnetic metallic material. The 3D bulk layered crystalline structures of CoX 2 (X = S, Se, and Te) are found to be nonmagnetic metals in our calculations. In addition to the major contributions due to the d orbitals of Co atoms, there is also contribution from the p orbitals of chalcogen X atoms to the electronic structure near the Fermi level of CoX 2 . We are optimistic for the experimental growth and uses of these monolayer structures for the 2D spintronic applications.