Room-temperature ferromagnetism via superexchange in semiconductor (Cr_4/6, Mo_2/6)₃Te₆

Realizing ferromagnetic semiconductors with high Curie temperature T_C is still a challenge in spintronics. Recent experiments have reported two-dimensional (2D) room temperature ferromagnetic metals, such as monolayer Cr₃Te₆. In this paper, by the density functional theory (DFT) calculations, we proposed a way to obtain 2D high T_C ferromagnetic semiconductors through element replacement in these ferromagnetic metals. We predict that monolayer (Cr_4/6, Mo_2/6)₃Te₆, created via element replacement in monolayer Cr₃Te₆, is a room-temperature ferromagnetic semiconductor exhibiting a band gap of 0.34 eV and a T_C of 384 K. Our analysis reveals that the metal-to-semiconductor transition stems from the synergistic interplay of Mo-induced lattice distortion, which resolves band overlap, and the electronic contributions of Mo dopants, which further drive the formation of a distinct band gap. The origin of the high T_C is traced to strong superexchange coupling between magnetic ions, analyzed via the superexchange model with DFT and Wannier function calculations. Considering the fast developments in fabrication and manipulation of 2D materials, our theoretical results propose a way to explore the high temperature ferromagnetic semiconductors from experimentally obtained 2D high temperature ferromagnetic metals through element replacement.