Topological Characterization of Classical Waves: The Topological Origin of Magnetostatic Surface Spin Waves
- Authors
- Yamamoto, Kei; Thiang, Guo Chuan; Pirro, Philipp; Kim, Kyoung-Whan; Everschor-Sitte, Karin; Saitoh, Eiji
- Issue Date
- 2019-05-29
- Publisher
- AMER PHYSICAL SOC
- Citation
- PHYSICAL REVIEW LETTERS, v.122, no.21
- Abstract
- We propose a topological characterization of Hamiltonians describing classical waves. Applying it to the magnetostatic surface spin waves that are important in spintronics applications, we settle the speculation over their topological origin. For a class of classical systems that includes spin waves driven by dipole-dipole interactions, we show that the topology is characterized by vortex lines in the Brillouin zone in such a way that the symplectic structure of Hamiltonian mechanics plays an essential role. We define winding numbers around these vortex lines and identify them to be the bulk topological invariants for a class of semimetals. Exploiting the bulk-edge correspondence appropriately reformulated for these classical waves, we predict that surface modes appear but not in a gap of the bulk frequency spectrum. This feature, consistent with the magnetostatic surface spin waves, indicates a broader realm of topological phases of matter beyond spectrally gapped ones.
- Keywords
- BULK-EDGE CORRESPONDENCE; MODES; BULK-EDGE CORRESPONDENCE; MODES; 위상학; 스핀파
- ISSN
- 0031-9007
- URI
- https://pubs.kist.re.kr/handle/201004/119974
- DOI
- 10.1103/PhysRevLett.122.217201
- Appears in Collections:
- KIST Article > 2019
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