Regensburg 2022 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 24: Spin Transport and Orbitronics, Spin-Hall Effects

MA 24.8: Vortrag

Mittwoch, 7. September 2022, 16:45–17:00, H37

Hidden current-induced spin and orbital torques in bulk Fe₃GeTe₂ from first-principles — •Tom G. Saunderson^1,2, Dongwook Go^1,2, Stefan Blügel², Mathias Kläui^1,3, and Yuriy Mokrousov^1,2 — ¹Institute of Physics, JGU, 55099 Mainz, Germany — ²PGI and IAS, Forschungszentrum Jülich, Germany — ³Centre for Quantum Spintronics, NTNU, 7491 Trondheim, Norway

Within the field of spintronics, the two dimensional (2D) van der Waals (vdW) material Fe₃GeTe₂ has been in the spotlight in the last few years for exciting characteristics such as nodal line semimetallicity [1], highly efficient spin-orbit torque switching [2] and skyrmion formation [3]. In a recent collaboration [4] we found that spin-orbit torques were observed within the bulk, yet the clean crystal’s bilayer system is centrosymmetric. Whilst this leads to overall vanishing spin-orbit torques, strong ‘hidden’ current-induced torques are harvested by each of the two-dimensional FGT layers separately. We demonstrate, from first principles [5], that an interplay of spin and orbital degrees of freedom has a profound impact on spin-orbit torques in this prototype material. We uncover a drastic difference in the behavior of the conventional spin flux torque and so-called orbital torque as the magnetization is varied resulting in a non-trivial evolution of switching properties. Our findings promote the design of non-equilibrium orbital properties as the guiding mechanism for crafting the properties of spin-orbit torques in layered vdW materials. [1] Nat. Mater. 794, 17 (2018) [2] Nano Lett. 4400, 19 (2019) [3] Nano Lett. 868, 20 (2020) [4] arXiv:2107.09420 [5] arXiv:2204.13052