Flat Bands, Indirect Gaps, and Unconventional Spin-Wave Behavior Induced by a Periodic Dzyaloshinskii-Moriya Interaction
| Autor: | Kilian Lenz, David Cortés-Ortuño, Jürgen Lindner, R. A. Gallardo, A. Roldán-Molina, P. Landeros, Roberto E. Troncoso, T. Schneider, Hans Fangohr, Fusheng Ma |
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| Rok vydání: | 2019 |
| Předmět: |
Physics
Antisymmetric exchange Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics Band gap Magnon Physics::Optics FOS: Physical sciences General Physics and Astronomy Metamaterial Context (language use) Condensed Matter - Soft Condensed Matter 01 natural sciences Condensed Matter - Other Condensed Matter Ferromagnetism Spin wave Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences Soft Condensed Matter (cond-mat.soft) Condensed Matter::Strongly Correlated Electrons 010306 general physics Electronic band structure Other Condensed Matter (cond-mat.other) |
| Zdroj: | Physical Review Letters |
| ISSN: | 1079-7114 0031-9007 |
| DOI: | 10.1103/physrevlett.122.067204 |
| Popis: | Periodically patterned metamaterials are known for exhibiting wave properties similar to the ones observed in electronic band structures in crystal lattices. In particular, periodic ferromagnetic materials are characterized by the presence of bands and bandgaps in their spin-wave spectrum at tunable GHz frequencies. Recently, the fabrication of magnets hosting Dzyaloshinskii-Moriya interactions has been pursued with high interest since properties such as the stabilization of chiral spin textures and nonreciprocal spin-wave propagation emerge from this antisymmetric exchange coupling. In this context, to further engineer the magnon band structure, we propose the implementation of magnonic crystals with periodic Dzyaloshinskii-Moriya interactions, which can be obtained, for instance, via patterning of periodic arrays of heavy-metals wires on top of an ultrathin magnetic film. We demonstrate through theoretical calculations and micromagnetic simulations that such systems show an unusual evolution of the standing spin waves around the gaps in areas of the film that are in contact with the heavy-metal wires. We also predict the emergence of indirect gaps and flat bands and, effects that depend on the strength of the Dzyaloshinskii-Moriya interaction. This study opens new routes towards engineered metamaterials for spin-wave-based devices. Comment: 6 pages, 3 figures |
| Databáze: | OpenAIRE |
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