Switchable half-metallicity in anti-ferromagnetic bilayer NbS2

Abstract

Electrical control over spin in spintronics has many advantages over magnetic control such as improved efficiency, reduced energy consumption, enhanced compatibility and faster response. However, direct electrical control also has its disadvantage due to its volatility feature, and thus indirect electrical control with the aid of ferroelectric materials is much more attractive. In this work, we propose another indirect electrical control strategy based on sliding ferroelectricity to achieve half-metallicity in antiferromagnetic bilayer NbS₂. Based on density functional theory calculations, it is found that switchable sliding interlayer ferroelectricity can be produced. The built-in electrical field from the resultant out-of-plane polarization can induce a potential energy difference between the two layers, which leads to spin splitting in the band structure. Although the sliding ferroelectricity is generally weak as compared to those intrinsic ferroelectric 2D materials, the spin splitting is strong enough to close the band gap of one of the spin channels and lead to half-metallicity in the antiferromagnetic bilayer NbS₂. Our study provides an alternative method to realize sliding induced switchable half-metallicity in 2D antiferromagnetic bilayer systems and thus to extend their practical applications.