Theoretical Study Of Two-dimensional Magnetic Material CrI₃ Defects By First Principles Method

With unique electronic and magnetic properties,a two-dimensional(2D)direct band gap,Chromium iodinate(CrI₃)has a great potential for spintronic applications.Under the guidance of the defect theoretical,we investigated the structures,thermodynamic,electronic and magnetic properties of CrI₃ defects with different types by the first principles study.Twenty kinds of point defects,including vacancies,interstitial,substitution and bond-rotation defects have been investigated firstly.With the variance of the chemical potential of iodide,the metalloid or metallic single atom vacancies is energetic stable,and leading to the intrinsic n-type and p-type doping,respectively.Interestingly,the transition of ferromagnetic to antiferromagnetic can be induced by the most of point defects,which can be explored by the simple Heisenberg model.As an inevitable line defect,the investigation of edge effective is still necessary.Then,we investigate the thermodynamic stabilities,electronic,and magnetic properties of thirteen CrI₃edges with different structures.The zigzag edges are more stable than armchair edges in CrI₃ ribbon,and the metallic and insulating properties can be induced by zigzag edges with the different chemical growth conditions.We investigate the stability and the associated electronic properties according to the octahedron ligand field and electron counting model.Both the magnetic moment and Curie temperature are enhanced by induced the edges,which is in startle contrast to surfaces of three-dimensional ferromagnetic materials where a magnetic dead layer is often observed.Finally,the exploration of thirteen grain boundary finds that,the most stable structures are the GB-8-2 and GB-8-0 grain boundaries.Meanwhile,the metallic and insulating properties can be induced by different experiment.The magnetic moment of CrI₃ grain boundary is strong dependent with the change of Cr-Cr bond length.The content of present investigation contributes to the atomic-scale understanding of the electric and magnetic properties of monolayer CrI₃ defects and the application guide on2D magnetic materials by defect engineering.