Controllable high Curie temperature through 5d transition metal atom doping in CrI₃

Two-dimensional (2D) CrI₃ is a ferromagnetic semiconductor with potential for applications in spintronics. However, its low Curie temperature (T_c) hinders realistic applications of CrI₃. Based on first-principles calculations, 5d transition metal (TM) atom doping of CrI₃ (TM@CrI₃) is a universally effective way to increase T_c, which stems from the increased magnetic moment induced by doping with TM atoms. T_c of W@CrI₃ reaches 254 K, nearly six times higher than that of the host CrI₃. When the doping concentration of W atoms is increased to above 5.9%, W@CrI₃ shows room-temperature ferromagnetism. Intriguingly, the large magnetic anisotropy energy of W@CrI₃ can stabilize the long-range ferromagnetic order. Moreover, TM@CrI₃ has a strong ferromagnetic stability. All TM@CrI₃ change from a semiconductor to a half-metal, except doping with Au atom. These results provide information relevant to potential applications of CrI₃ monolayers in spintronics.