Magnetic properties of ultrathin layered chromium di-telluride*

Based on ab initio calculations we have studied the magnetic properties of two dimensional chromium di-telluride CrTe₂ in the few layers limit and the bulk. We find that for both trigonal (H) and octahedral (T) structures the CrTe₂ multilayers exhibit intralayer ferromagnetism and layer thickness dependent interlayer magnetic coupling. The layer anti-ferromagnetism (L-AFM) is stabilized in bi- and tri- layer systems, but we find a transition to the layer ferromagnetic (L-FM) phase for a tetralayer. The magnetic anisotropy calculations reveals that single layers are in-plane magnets for both H-CrTe₂ and T-CrTe₂ systems while in the bulk they have respectively out-of-plane and in-plane magnetizations. For T-CrTe₂ the easy axis orientation is found to align with increasing anisotropy energy towards the out-of-plane direction for the bi-, tri- and tetra layers, in contrast to the magnetisation behavior in the bulk. We explore the anisotropy energy increase with layer number in connection with the atomic structural distortions present in ultrathin multilayers.