Tunable electronic and magnetic properties of monolayer electride Hf2S by N decorating

Abstract

Electrides have attracted considerable attention in both experimental and theoretical research owing to the unique electron distribution characteristics in real space. The presence of free-electron gas in electrides increases the flexibility in regulating its physical properties. Here, we systematically investigate the electronic and magnetic properties of monolayer Hf₂S via N-atom adsorption. We find that one-side-coverage N atoms can regulate the system to change from an antiferromagnetic metal to a ferromagnetic half-metal. The physical origin of the ferromagnetic property can be elucidated by the Stoner mechanism. Notably, two-side-coverage N atoms will further transform the system to a nonmagnetic semiconductor with large valley splitting at the K and K’ valleys. When applied an in-plane electric field, the valley Hall and spin Hall effects occurred due to optical excitation and charge doping. With these flexible properties, N-absorbed monolayer Hf₂S exhibits significant potential applications in future electronic, spintronic, and valleytronic devices.