Switchable electronic and enhanced magnetic properties of CrI₃ edges

Owing to its novel electronic and magnetic properties, two-dimensional CrI₃ has great potential in the application of spintronic devices. However, as an inevitable line defect, the properties of the edges of CrI₃ remain elusive. Here, via first-principles calculations with spin-orbit coupling, we investigated the thermodynamic stabilities, electronic and magnetic properties of thirteen CrI₃ edges with different structures. We showed that zigzag edges are more stable than armchair edges, and a CrI₃ nanoribbon can be either metallic or insulating depending on its chemical growth conditions. The edge stability and associated electronic properties can be understood in terms of the octahedron ligand field and electron counting model. In most cases, both the magnetic moment and Curie temperature can be enhanced by edges, which are in startle contrast to the surfaces of three-dimensional ferromagnetic materials, where a magnetic dead layer is often observed.