Journal Article

FZJ-2023-05907

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Long-Range Orbital Torque by Momentum-Space Hotspots

Go, D. (Corresponding author)FZJ* ; Jo, D. ; Kim, K.-W. ; Lee, S. ; Kang, M.-G. ; Park, B.-G. ; Blügel, S.FZJ* ; Lee, H.-W. ; Mokrousov, Y.FZJ*

2023
APS College Park, Md.

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Please use a persistent id in citations: doi:10.1103/PhysRevLett.130.246701  doi:10.34734/FZJ-2023-05907

Abstract: While it is often assumed that the orbital response is suppressed and short ranged due to strong crystal field potential and orbital quenching, we show that the orbital response can be remarkably long ranged in ferromagnets. In a bilayer consisting of a nonmagnet and a ferromagnet, spin injection from the interface results in spin accumulation and torque in the ferromagnet, which rapidly oscillate and decay by spin dephasing. In contrast, even when an external electric field is applied only on the nonmagnet, we find substantially long-ranged induced orbital angular momentum in the ferromagnet, which can go far beyond the spin dephasing length. This unusual feature is attributed to nearly degenerate orbital characters imposed by the crystal symmetry, which form hotspots for the intrinsic orbital response. Because only the states near the hotspots contribute dominantly, the induced orbital angular momentum does not exhibit destructive interference among states with different momentum as in the case of the spin dephasing. This gives rise to a distinct type of orbital torque on the magnetization, increasing with the thickness of the ferromagnet. Such behavior may serve as critical long-sought evidence of orbital transport to be directly tested in experiments. Our findings open the possibility of using long-range orbital response in orbitronic device applications.

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Contributing Institute(s):

1. Quanten-Theorie der Materialien (PGI-1)
2. Quanten-Theorie der Materialien (IAS-1)
3. JARA - HPC (JARA-HPC)
4. JARA-FIT (JARA-FIT)

Research Program(s):

1. 5211 - Topological Matter (POF4-521) (POF4-521)
2. DFG project 437337265 - Spin+Optik: Theoretischer Entwurf von antiferromagnetischer Optospintronik (A11) (437337265) (437337265)
3. DFG project 444844585 - Statische und dynamische Kopplung von Gitter- und elektronischen Freiheitsgraden in magnetisch geordneten Übergangsmetalldichalkogenieden (B06) (444844585) (444844585)

Appears in the scientific report 2023

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Database coverage:
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