Light-mediated magnetism in atomically thin vanadium-doped tungsten disulfide semiconductors

Abstract

Atomically thin transition metal dichalcogenides (TMD) semiconductors hold enormous potential for modern optoelectronic and ultra-low powered devices. By inducing long-range ferromagnetism (FM) in these semiconductors through the introduction of small amounts of a magnetic dopant, it is possible to extend their potential in emerging spintronic applications [1,2]. Our recent study showed that room temperature magnetism is achieved in V-doped WS2 monolayers [3], while still maintaining its characteristic optical properties. In this work we demonstrate light-mediated, room temperature FM, in V-doped WS2 monolayers. We probe this effect using the principle of magnetic LC resonance [4], which employs a soft ferromagnetic Co-based microwire coil driven near resonance in the radio frequency regime. Combining LC resonance, with an outstanding giant magneto-impedance effect, renders the coil highly sensitive to changes in the magnetic flux through its core. The V-doped WS2 monolayer is placed at the core of the coil where it is excited with a laser, while its magnetic permeability is probed by the coil. We found that the magnetic permeability of the monolayers is dependent on laser intensity, confirming light control of room temperature magnetism in this two-dimension material. Density functional theory calculations lead us to understand that this phenomenon is a consequence of an accumulation of excess holes in the conduction and valence bands, as well as carriers trapped in the magnetic doping states, which in turn mediates the magnetization of V-WS2 monolayers. These findings provide a promising route to exploit light-controlled FM in two-dimensional TMD based spintronic devices.