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

We investigate spin-polarized electronic structures of CoX2 (X = S, Se, and Te) monolayers using the density functional theory. We find that CoS2 and CoSe2 monolayers are metallic ferromagnetic materials, whereas CoTe2 monolayer is nonmagnetic metallic material. The 3D bulk layered crystalline structures of CoX2 (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 CoX2. We are optimistic for the experimental growth and uses of these monolayer structures for the 2D spintronic applications.