Light wave dynamics driving attosecond coherent spins and topological systems

Markus Münzenberg, Greifswald University

Ultrafast magnetism and THz spintronics allows meanwhile insightful concepts on spin-waves heating and spin-currents on femtosecond timescales. We think of novel applications and new proof of concept studies for ultrafast spintronic devices [1,2,3].

New experimental approaches allows to go even faster. Central is the light wave oscillating at attoseconds that drives the dynamics and spin response depends on the energy transfer from the laser excited electrons to the spins. It seems thus appealing to study ultrafast spin dynamics on these time scales, in order to see if the spin response can be detected coherent to the light waves’s oscillation.

Attosecond lasers are breaking new frontiers. We demonstrate coherent charge transfer, driven by a few cycle laser pulse in a spintronic layered device. This allows to drive coherent attosecond magnetism [4]. Experimental and theoretical sides of the study revealing coherent electron transfer at interfaces, and I will connect this to possible applications of coherent processes and light driven topological dynamics and spintronic devices going into wave-cycle operation.

[1] J. Walowski and M. Münzenberg, Perspective: Ultrafast magnetism and THz spintronics, J. Appl. Phys. 120 140901 (2016)
[2] T. Kampfrath, et al. Terahertz spin current pulses controlled by magnetic heterostructures, Nature Nanotech. 8, 256 (2013)
[3] T. Seifert, et al. Efficient metallic spintronic emitters of ultrabroadband terahertz radiation, Nature Photon. 10, 483–488 (2016)
[4] F. Siegrist et al., Light-wave dynamic control of magnetism, Nature 571 (2019)

PDF file of the talk available here