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Twisted magnon beams carrying orbital angular momentum
Chenglong Jia1, Decheng Ma2, Alexander F Schäffer3
1Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education and Institute of Theoretical Physics, Lanzhou University, 73000, Lanzhou, China. cljia@lzu.edu.cn.
Nature Communications
|May 9, 2019
Summary
Researchers have discovered twisted spin waves, or magnons, that carry orbital angular momentum (OAM). This OAM is electrically controllable and protected against damping, enabling new possibilities for magnonic computing.
Area of Science:
- Spintronics
- Condensed Matter Physics
Background:
- Spin waves (magnons) are low-energy excitations in ferromagnets.
- They offer lossless information transfer and processing in magnonic circuits.
- Current magnonic technologies lack electrical tunability and robust OAM control.
Purpose of the Study:
- To introduce and characterize novel spin waves with electrically controllable orbital angular momentum (OAM).
- To demonstrate the emergence, topological quantification, and steering of these twisted magnon beams.
- To explore the potential of OAM-based magnonics for computing and quantum information.
Main Methods:
- Theoretical modeling of spin wave propagation in magnonic waveguides.
- Analysis of topological properties and OAM quantification.
- Investigation of electric field coupling via the Aharanov-Casher effect.
Main Results:
- Demonstrated the existence of twisted magnon beams carrying definite OAM.
- Showed that the topological charge of OAM is externally tunable via electric fields.
- Established that OAM is robust against magnetic damping.
- Identified a mechanism for electrically controlling OAM in magnonic systems.
Conclusions:
- Twisted magnon beams with electrically controllable OAM represent a significant advancement in magnonics.
- This technology enables robust, low-energy multiplexed magnonic computing.
- It opens new avenues for studying OAM-based entanglement at shorter wavelengths and lower energy costs.
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