Realizing Ferromagnetism in a Field-Effect Transistor Based on VSe2 Thin Flakes

Ferromagnetic order in 2D2D materials has triggered widespread interest because of their applications in spintronic devices. Monolayer 1T-VSe 2 , as a recently emerged candidate of 2D2D ferromagnetic material, exhibits complicated behaviors that contradict the theoretical predictions. In this work, a systematic investigation is presented on the evolution of the transport properties in VSe 2 thin flakes controlled by gate voltage. Notably, for the first time, a paramagnetic-to-ferromagnetic transition is realized in a VSe 2 thin flake using a field-effect transistor setup with solid ion conductor of polycrystalline Li 1+ x + y Al x (Ti 2− y Ge y )P 3− z Si z O 12 serving as the gate dielectric. The Curie temperature determined from the electrical transport measurements is ≈40 K. The electric-field-controlled ferromagnetism in exfoliated VSe 2 flakes provides an excellent platform for developing advanced spintronics as well as investigating unusual emergent physics in 2D systems.