Two-dimensional Cr₂Cl₃S₃ Janus Magnetic Semiconductor with large magnetic exchange interaction and high-T C

The two-dimensional (2D) Janus monolayers are promising in spintronic device application due to their enhanced magnetic couplings and Curie temperatures. Van der Waals CrCl 3 monolayer has been experimentally proved to have an in-plane magnetic easy axis and a low Curie temperature of 17 K, which will limit its application in spintronic devices. In this work, we propose a new Janus monolayer Cr 2 Cl 3 S 3 based on the first principles calculations. The phonon dispersion and elastic constants confirm that Janus monolayer Cr 2 Cl 3 S 3 is dynamically and mechanically stable. Our Monte Carlo simulation results based on magnetic exchange constants reveal that Janus monolayer Cr 2 Cl 3 S 3 is an intrinsic ferromagnetic semiconductor with T C of 180 K, which is much higher than that of CrCl 3 due to the enhanced ferromagnetic coupling caused by S substitution. Moreover, the magnetic easy axis of Janus Cr 2 Cl 3 S 3 can be tuned to the perpendicular direction with a large magnetic anisotropy energy (MAE) of 142 μeV/Cr. Furthermore, the effect of biaxial strain on the magnetic property of Janus monolayer Cr 2 Cl 3 S 3 is evaluated. It is found that the Curie temperature is more robust under tensile strain. This work indicates that the Janus monolayer Cr 2 Cl 3 S 3 presents increased Curie temperature and out-of-plane magnetic easy axis, suggesting greater application potential in 2D spintronic devices.