Modulating the electronic and optical properties of CrI3/In2Se3 van der Waals heterostructures by external fields

Abstract

The van der Waals heterostructures (vdWH) composed of two-dimensional (2D) magnetic materials and non-magnetic atomic layers provide promising candidates for innovative device design. Here, we construct the CrI3/α-In2Se3 vdWH and regulate its band structure, magnetism and optical absorption through external fields. The intrinsic vdWH possesses type-Ⅱ band alignment with 0.38 eV band gap. As a result of proximity effects and superexchange interaction, magnetism is induced in the α-In2Se3 layer. The Curie temperature of the vdWH with FM coupling has increased to 99.3 K. Interestingly, with the increasing of the applied electric field, the band alignment exhibits a transition from type-Ⅱ to type-Ⅰ and then back to type-Ⅱ. When the electric field is −4.31 V/nm, the vdWH convert from semiconductor to half-metal. Moreover, the applying biaxial and vertical strain can influence the energy level of hybridization, and transferred charges. For example, the increased magnetic moment of the CrI3 monolayer increased by four times when the distance gap is decreased by 0.5 Å. These properties can offer novel strategies for engineering band structure and regulating magnetic properties, thereby enabling researchers to design tunable multiferroic vdWH devices.