All-optical switching in a 2D van der Waals magnet CrI3

The discovery of magnetism in two-dimensional (2D) van der Waals (vdW) materials presents an unprecedented opportunity to understand the fundamental interactions between light and spins and develop novel device architectures. However, little is known about how laser pulses can affect the magnetic properties of 2D magnets. Here, we demonstrate laser-induced manipulation of magnetic domains within CrI 3 flakes. By fabricating CrI 3 /WSe 2 vdW heterostructures, we can additionally achieve full all-optical switching (AOS). The dependence of the AOS upon the polarization of the laser pulses agrees with the valley-dependent optical selection rules for WSe 2 , implying that spin-dependent interfacial charge transfer is the underpinning mechanism for the switching.