Tunable magnetic coupling and high Curie temperature of two-dimensional PtBr3 via van der waals heterostructures

Two-dimensional ferromagnetic semiconductors hold great promise for next-generation spintronic applications. However, candidates with high Curie temperature (T-c) are still lacking. Using the first-principles calculations, the PtBr3 monolayer is found to exhibit ferromagnetic order above the room temperature. The formation of PtBr3/WSe2 van der Waals heterostructures can increase the T-c to similar to 410 K by additional super-exchange path of Pt-Se-Pt. The spin-exchange interactions for this path is as strong as similar to 22 meV, which is superior to most other magnetic system. The out-of-plane compression further boosts the T-c to similar to 636 K. The interlayer magnetic coupling is highly tunable depending on the stacking alignment, which closes or weakens some super-exchange channels. In addition, the interlayer interaction leads to a phase transition from half-metal to semiconductor, which greatly promotes its potential in spintronic applications. The strong stacking dependent feature is feasible to manipulate the magnetic orders by external strain or mechanical motion.