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Theory of charge and spin pumping in atomic-scale spiral magnets

Kurebayashi, Daichi; Liu, Yizhou; Masell, Jan 1; Nagaosa, Naoto
1 Institut für Theoretische Festkörperphysik (TFP), Karlsruher Institut für Technologie (KIT)

Abstract:

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 $\omega$. In the present paper, 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 $\omega$ whereas the spin current is $\omega^2$ for small $\omega$. 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 $\lambda$ but decays with $\lambda^{-1}$ for longer pitches, unlike true Thouless pumps or Archimedian screws. Moreover, we study the onset of non-adiabaticity (large $\omega$), the impact of attached non-magnetic or magnetic contacts, and the real-time evolution of the transport observables. Finally, we analyze the effects of disorders which, surprisingly, might enhance the spin current but suppress the charge current.


Volltext §
DOI: 10.5445/IR/1000153439
Veröffentlicht am 02.12.2022
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Theoretische Festkörperphysik (TFP)
Publikationstyp Forschungsbericht/Preprint
Publikationsjahr 2022
Sprache Englisch
Identifikator KITopen-ID: 1000153439
Umfang 18 S.
Vorab online veröffentlicht am 14.01.2022
Nachgewiesen in arXiv
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