6533b852fe1ef96bd12aae16
RESEARCH PRODUCT
古典波動現象のトポロジーによる特徴付け; 静磁スピン波表面モードのトポロジカルな起源
Karin Everschor-sittePhilipp PirroEiji SaitohEiji SaitohEiji SaitohKei YamamotoKei YamamotoKyoung-whan KimKyoung-whan KimGuo Chuan Thiangsubject
Hamiltonian mechanicsSurface (mathematics)PhysicsCondensed Matter - Mesoscale and Nanoscale PhysicsSpintronicsFOS: Physical sciencesGeneral Physics and AstronomyPhysik (inkl. Astronomie)Topology01 natural sciencesVortexBrillouin zonesymbols.namesakeSpin waveMesoscale and Nanoscale Physics (cond-mat.mes-hall)0103 physical sciencessymbols010306 general physicsTopology (chemistry)Symplectic geometrydescription
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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2019-01-01 | Physical review letters |