Topological Magnon Bands in a Kagome Lattice Ferromagnet
Name
PhysRevLett.115.147201.pdf
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1.68 MB
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Author(s)
Helton, J. S.
Singh, D. K.
Bewley, R. I.
Chisnell, Robin
Freedman, Danna
Nocera, Daniel G.
Lee, Young S.
Date Issued
September 2015
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Chisnell, R., J. S. Helton, D. E. Freedman, D. K. Singh, R. I. Bewley, D. G. Nocera, and Y. S. Lee. "Topological Magnon Bands in a Kagome Lattice Ferromagnet." Phys. Rev. Lett. 115, 147201 (September 2015). © 2015 American Physical Society
Version
Final published version
Abstract
There is great interest in finding materials possessing quasiparticles with topological properties. Such materials may have novel excitations that exist on their boundaries which are protected against disorder. We report experimental evidence that magnons in an insulating kagome ferromagnet can have a topological band structure. Our neutron scattering measurements further reveal that one of the bands is flat due to the unique geometry of the kagome lattice. Spin wave calculations show that the measured band structure follows from a simple Heisenberg Hamiltonian with a Dzyaloshinkii-Moriya interaction. This serves as the first realization of an effectively two-dimensional topological magnon insulator—a new class of magnetic material that should display both a magnon Hall effect and protected chiral edge modes.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.115.147201
