Interface engineering of VSe2/LaFeO3 vertical heterostructures: modulation of magnetic and electronic properties

Abstract

We performed first-principles calculations based on density functional theory to investigate the atomic structure, electronic properties, and magnetic behavior of monolayer and bilayer 1T- and H-VSe₂ adsorbed on the (001) surface of LaFeO₃ (LFO) with LaO and FeO₂ termination layers, respectively. Our findings reveal that both monolayer and bilayer VSe₂ can stably adhere to the LFO (001) surface. Monolayer 1T- and H-VSe₂ exhibit ferromagnetic (FM) characteristics, where the 1T phase is metallic and the H phase is semiconducting. Charge transfer from LFO to VSe₂ induces the reversal of the magnetic moments for specific V atoms in VSe₂, leading to in-plane antiferromagnetic (AFM) properties. Monolayer 1T-VSe₂ on the LFO surface retains metallic, whereas monolayer H phase exhibits diverse behaviors: some configurations preserve their semiconducting properties, while others transition to metallic states. For bilayer VSe₂/LFO heterostructures, both 1T- and H-bilayer VSe₂ exhibit interlayer AFM alignment and in-plane FM states. Bilayer 1T-VSe₂ maintains its metallic character, while bilayer H-VSe₂ with LaO termination exhibits half-metallic properties, and that with FeO₂ termination retains semiconducting, enabling tunable half-metal/semiconductor transitions via LFO substrate engineering. Finally, we explored the hydrogen evolution reaction (HER) catalytic performance of single-atom Pt-doped VSe₂ with and without the LFO (001) substrate. The results indicate that the presence of the LFO substrate significantly enhances the stability of single-atom Pt on VSe₂ and improves the HER catalytic efficiency for Pt-doped monolayer VSe₂. Additionally, the monolayer H-VSe₂/LFO heterostructure demonstrates potential for Z-scheme photocatalytic applications.