Probing Ultrafast Spin Transport with Terahertz Electromagnetic Pulses

Tobias Kampfrath, Freie Universität Berlin and Fritz Haber Institute of the Max Planck Society

February 11, 2022

To take advantage of the electron spin in future electronics, spin angular momentum needs to be transported and detected. Electric fields and temperature gradients have been shown to efficiently drive spin transport at megahertz and gigahertz frequencies. However, to probe the initial elementary steps that lead to the formation of spin currents, we need to launch and measure transport on much faster, that is, on femtosecond time scales. This goal is achieved by employing ultrashort optical and terahertz electromagnetic pulses in conjunction with spin-orbit coupling. We obtain new insights into important spintronic phenomena such as spin-caloric transport [1], spin-to-charge-current conversion [2] and anisotropic magnetoresistance [3]. Interesting photonic applications such as the generation of ultrashort terahertz electromagnetic pulses also emerge [4].


[1] S.M. Rouzegar et al., arXiv:2103.11710 (2021)
[2] Gueckstock et al., Advanced Materials 2006281 (2021)
[3] Nadvorník et al., Physical Review X 11, 021030 (2021)
[4] Seifert et al., Nature Photon. 10, 483 (2016); Fülöp et al., Advanced Optical Materials 1900681 (2019)