Ultrafast Spin Current Generation from an Antiferromagnetic Insulator

Di Wu, Nanjing University

March 26, 2021

Antiferromagnets (AFMs) have the potential to push spintronic devices from the static or gigahertz frequency range to the terahertz (THz) range for the sake of the high-speed processing. However, the insensitivity of AFMs to magnetic fields also makes it hard to manipulate spin currents. While the ultrafast generation of the spin current in ferromagnet/heavy metal (FM/HM) structures has received a lot of attention in recent years, it is still unknown as to whether a similar scenario can be observed in an AFM/HM system. Here we show the optical generation of ultrafast spin current in an AFM/HM heterostructure at zero external magnetic field and at room temperature by detecting the associated THz emission. We believe this is a common phenomenon in antiferromagnets with strong nonlinear optical effects. Our results open an avenue of fundamental research into antiferromagnetism and a route to AFM spintronic devices.

[1] Qiu et al., Ultrafast spin current generated from an antiferromagnet, Nature Physics, 17, 388 (2021).