Induced half-metallic characteristics and enhanced magnetic anisotropy in the two-dimensional Janus V2I3Br3 monolayer by graphyne adsorption.

Abstract

The recent emergence of two-dimensional (2D) Janus materials has opened a new avenue for spintronic and optoelectronic applications. However, 2D magnetic Janus materials and Janus monolayer-based magnetic heterostructures are yet to be fully studied. Herein, the stability and electronic structure of 2D Janus V2I3Br3 and V2I3Cl3 monolayers, and the electronic and magnetic properties of 2D graphyne/Janus V2I3Br3 (γ-GY/V2I3Br3) heterostructures are calculated based on the density functional theory. Janus V2I3Br3 and V2I3Cl3 monolayers are ferromagnetic semiconductors with good stability and direct band gap. By combing the graphyne layer, the Janus V2I3Br3 monolayer shows half-metallic characteristics. The electrical conductivity of the Janus V2I3Br3 monolayer in γ-GY/V2I3Br3 heterostructures is further improved, which is very favorable for the applications of the γ-GY/V2I3Br3 heterostructure in battery anodes. Moreover, the Janus V2I3Br3 monolayer possesses a smaller perpendicular magnetic anisotropy (PMA), and the PMA can be effectively enhanced by combing γ-GY. Herein, the enhanced PMA was discovered to depend on the stacking patterns of γ-GY and V2I3Br3 monolayers. Biaxial strains can further affect the PMA of the γ-GY/V2I3Br3 heterostructure. Meanwhile, at a compressive strain, the Janus V2I3Br3 monolayer in the γ-GY/V2I3Br3 heterostructure realizes the transition from the magnetic half-metallic to the magnetic metal state. These results can enrich the applications and designs of γ-GY/V2I3Br3 magnetic heterostructures in spintronic devices and energy fields.