First-principles approach to novel 2D ferromagnets

There is currently an increasing enthusiasm towards long-range magnetic order in two-dimensional materials (such as CrI3 and Cr2Ge2Te6), from the fundamental and from the applicative point of view, from theory and from experiments. In this work, we carry out an extensive investigation based on density functional theory on an extended class of such materials, starting from the database of exfoliable materials reported in N. Mounet et al., Nature Nano. 13, 26 (2018). In the aim of optimizing the properties of 2D-ferromagnets, in particular focusing on an increase of the Curie temperature, our analysis ranges from semiconducting chalcohalides (with formula M-VI-VI, where M is a transition metal, VI and VII are chalcogen and halogen elements) to di-halides (with formula M-(VII)2). In addition to structural and electronic properties, we analyse magnetic properties, in terms of magnetic moments, Heisenberg exchange coupling constants and magnetic anisotropy energy. Some of the considered materials (such as CrSBr or NiBr2) show exchange coupling constants significantly larger than the prototypical CrI3, so they might be promising candidates for larger transition temperatures.