First principles studies of electric field-driven half-metallicity in the ferromagnetic Janus VSSe bilayer

2D half-metallic ferromagnets are promising materials for spintronics, which exploit the electron's intrinsic spin for novel information processing and storage devices. This study aims to expand the known space of such 2D ferromagnetic (FM) half-metals by exploring the electronic and magnetic properties of a bilayer of Janus VSSe, a FM semiconductor [1], using density functional theory. The GGA+U method is employed to account for on-site interactions on the Vanadium 3d orbitals. Magnetic anisotropy calculations performed including spin orbit coupling, manifested an easy plane of magnetization for the considered VSSe bilayer. The VSSe bilayer exhibits a small band gap of 0.11 eV with energy states close to the Fermi level from the same spin channel, i.e., majority spins, and the minority spin carriers possess a band gap of 0.60 eV. To induce a semiconductor-to-half-metal transition, the VSSe bilayer is subjected to an external electric field of varying strengths normal to the plane. Band gap decreases for both the spin channels with increasing strength of applied electric field. Remarkably, half-metallic behavior is achieved at a low field strength of approximately 0.18 V/Å, a practically feasible value [2]. These findings predict FM Janus VSSe bilayer as a potential candidate for spintronic devices.

1. Dey et al., Phys. Rev. Mater. 4, 074002 (2020).

2. Weintrub et al., Nat Commun 13, 6601 (2022).