2022 Fiscal Year Annual Research Report
Magnon spin-orbit torques in two-dimensional van der Waals magnets based heterostructures
| Project/Area Number |
22K14561
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| Research Institution | Keio University |
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Principal Investigator |
高 藤華 慶應義塾大学, 理工学研究科(矢上), 助教 (60896851)
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| Project Period (FY) |
2022-04-01 – 2023-03-31
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| Keywords | Spin-orbit torques / Energy barrier / Spin mixing conductance / Topological semimetal / Spin Hall effect |
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| Outline of Annual Research Achievements |
To develop two-dimensional van der Waals crystal based magnon spin-orbit torque devices, the first crucial step is to find an efficient spin polarization source that can be used to activate magnon spin current. By designing a metal-magnet/topological semimetal heterostructure, we find that the bulk spin Hall effect of the semimetal is sizable, leading to a high spin-orbit torque generation efficiency comparable to that in heavy metal based heterostructures. Strikingly, we show evidence that the energy barrier exists even in metal-magnet/semimetal heterojunctions, which governs spin transport manifested as a large observed field-like spin-orbit torque and thus a large imaginary part of the spin mixing conductance contrary to conventional wisdom, providing a new spin transport mechanism.
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