Manipulating light-wave-controlled charges into a spin-asymmetric flow: Petahertz frequency control of spins

Proposing a theoretical model of a layered ferromagnetic (FM) -nonmagnetic (NM) heterostructure under few-cycle optical driving, we render the light-wave-induced charge transport spin asymmetric and achieve petahertz frequency control of spins. Transition-metal trichalcogenides (TMTCs) are suggested for the FM layer. With the strong FM TMTCs (i.e., high-spin TM3+ therein), major and minor spins undergo cross transfer to the NM and FM layers, respectively, whereas with the weak FM TMTCs (i.e., low-spin TM3+), only major spins are transferred to the NM layer due to the Coulomb blockade for minor spins. These findings present prototypes of petahertz spin devices, broadening the horizon of spintronics up to the subfemtosecond time span.