Light-Induced Ultrafast Enhancement of Magnetic Orders in Monolayer CrX3

The recent discovery of light-tunable intrinsic ferromagnetismin two-dimensional (2D) van der Waals crystals has opened up a newarena for spintronics. However, the underlying mechanism is stillunder debate. Here, we performed excited-state density functionaltheory (DFT) calculations for optical manipulation of magnetism inmonolayered CrX3 (X = Cl, Br, I). By applying the real-timetime-dependent DFT method, we found that the laser pulses can directlyinduce ultrafast spin-selective charge transfer from X atoms to Cratoms and further generate a dramatic magnetic moment of Cr atom changes.The microscopic mechanisms for ultrafast changing of magnetic orderare discussed based on the p-d electron transition and electron-phononcoupling. Combined with constrained DFT and Monte Carlo simulations,we further theorized the light-excited effects on exchange interactionand found that the Curie temperature of CrX3 under lightexcitation (>150 K) is significantly higher than that in the groundstate (<70 K). Our results open new opportunities to manipulatethe spin in 2D magnets as well as the potential applications in spintronics.

Automated summary

The recent discovery of light-tunable intrinsic ferromagnetism in two-dimensional van der Waals crystals has opened up new possibilities for spintronics. This study investigates the optical manipulation of magnetism in monolayered CrX3 through excited-state density functional theory (DFT) calculations. It was found that laser pulses can induce ultrafast spin-selective charge transfer and dramatic changes in the magnetic moment of Cr atoms. The results provide insights into the mechanisms of fast magnetic order changing and demonstrate the potential applications in spintronics.