Dresden 2026 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 12: Terahertz Spintronics

MA 12.5: Vortrag

Montag, 9. März 2026, 16:00–16:15, POT/0351

Orbital-torque driven excitation of Terahertz perpendicular standing spin wave (PSSW) modes — •Harshita Devda¹, Peter M. Oppeneer², and Ulrich Nowak¹ — ¹Fachbereich Physik, Universität Konstanz, Konstanz, Germany — ²Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden

Layered ferromagnets support interface-sensitive THz spin dynamics, making the controlled excitation of such THz magnon modes relevant for spintronics applications. Recent experiments show that asymmetric NM/FM/NM trilayers couple efficiently to THz fields via interfacial spin-orbit torques (SOTs)[1], emphasizing the importance of interface effects in THz spin dynamics.

Here, we employ atomistic spin-dynamics simulations using ab-initio exchange parameters in thin NM/Co/NM trilayers to investigate ultrafast magnon excitation in presence of asymmetric and symmetric SOT interfaces. SOTs are implemented using the induced spin and orbital moments from first principles calculations. Our simulations show that nanometer thick Co-layers host exchange-dominated PSSWs in 1-3 THz range. Crucially, the efficient excitation of these THz modes is governed by interfacial field-like orbital torques, which follow directly from our recent study on layer-resolved SOTs[2]. This work establishes orbital torques as a robust route to ultrafast magnon generation.

[1]Salikhov et al., Nat. Phys. 19, 529-535 (2023)

[2]Devda et al.,Phys. Rev. B 112, 144438 (2025)

Keywords: spin-orbit torque; THz magnon modes; atomistic spin dynamics simulations; perpendicular standing spin waves; Ultrafast magnon generation