Band engineering in intrinsically magnetic CrBr3 monolayer

Abstract

The discovery of the intrinsic magnetism of CrI3 monolayers (Nature2017, 546, 270) serves as a new platform to regulate electrons. In this study, the electronic structure of the CrBr3 monolayer, a sister compound of CrI3, has been studied based on the first principle calculations and band engineering strategies involving carrier doping, vacancies (Cr vacancy, Br vacancy and the co-presence of Cr and Br vacancies) and in-plane strain. An insulator to half metal character transition could be actualized via charge doping (both hole and electron doping) and Cr vacancy. With co-existing Cr and Br vacancies, the half metallic character is sensitive to the distance between the defects. In contrast, the insulating nature would survive under conditions of Br vacancy defect as well as in-plane strain; however, the cooperation of strain and carrier doping would lead to half metal behavior. With regard to stabilization of ferromagnetic coupling, hole doping, electron doping and tensile strain would be effective; hole doping is more efficient than electron doping, and the co-existence of hole doping and tensile strain would further enable this enhancement.