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.