Substrate effects on the magnetic properties of an epitaxial CrI2 monolayer

Thanks to the progress in 2D materials technology, van der Waals (vdW) materials with outstanding magnetic properties can be synthesised nowadays by epitaxial methods down to the mono/few layers. However, substrate choice might lead to unwanted issues compromising the achievement of the desired properties. On the other hand, substrate engineering represents an ideal playground for understanding low-dimensional magnetism. Our preliminary XAS/XMCD studies on the epitaxial Chromium diiodide, CrI2, monolayers (ML) grown by MBE on a metallic (gold) and an insulating (mica) substrate suggest respectively paramagnetic and ferromagnetic ground states at 4K, sometimes in contrast with early theoretical results. These dissimilar behaviours might be explained in terms of charge doping from the metallic substrate and/or lattice distortion affecting Cr local symmetry and the material ground state.