Regensburg 2022 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 24: Spin Transport and Orbitronics, Spin-Hall Effects
MA 24.12: Vortrag
Mittwoch, 7. September 2022, 17:45–18:00, H37
Theory of charge and spin pumping in atomic-scale spiral magnets — Daichi Kurebayashi1,2, Yizhou Liu1, •Jan Masell1,3, and Naoto Nagaosa1,4 — 1RIKEN CEMS, Wako, Japan — 2University of New South Wales, Sydney, Australia — 3Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany — 4University of Tokyo, Tokyo, Japan
An Archimedean screw is a classical pump that exploits the equivalence of rotation and translation in helices. Similarly, a spin spiral texture can pump charge and spin by rotating at a frequency. We study these pumping phenomena within a microscopic quantum model by both perturbation theory and numerical simulations. Inside the spiral region, the spin polarization and charge current are linear in the frequency whereas the spin current scales with its square. We find that the charge current is related to the mixed momentum-phason Berry phase which can be viewed as a novel approximate realization of a Thouless pump. It is nearly quantized in spirals with short pitch but decays with 1/lambda for longer pitches unlike true Thouless pumps or Archimedean screws. Moreover, we study the onset of non-adiabaticity, the impact of attached non-magnetic or magnetic contacts, the real-time evolution of the transport observables, and the efects of disorders which, surprisingly, might enhance the spin current but suppress the charge current.[1]
[1] D. Kurebayashi, Y. Liu, J. Masell, and N. Nagaosa, https://doi.org/10.48550/arXiv.2201.05446