Robust Above-Room-Temperature Ferromagnetism in Few-Layer Antimonene Triggered by Nonmagnetic Adatoms

2D ferromagnets have attracted considerable attention due to their strong potential in the post-Moore Law era. However, intrinsic 2D ferromagnetic materials typically suffer from suppressed Curie temperature due to thermal fluctuation, magnetic order instability in the 2D limit, and others. Herein, a nonmagnetic fluorine modification strategy is proposed to control the ferromagnetism of air-stable antimonene. It is demonstrated that fluorinated antimonene (F-antimonene), synthesized via an electrochemical exfoliation and synchronous fluorination method, exhibits robust ferromagnetism with a Curie temperature of up to 717 K (compared with a Curie temperature of 220 K for pristine antimonene) and a saturation magnetization of approximate to 0.1 emu g(-1) (determined by the fluorination degree). First-principles simulations confirm that the robust long-range ferromagnetic order in the half-metallic F-antimonene is induced by the low-density sp-electron-polarized impurity subbands. The study constitutes a nonmagnetic control of robust above-room-temperature ferromagnetism in monoelemental 2D semiconductors and paves a new route toward 2D atomic layer-based spin devices.