Topological Spin Excitations in Honeycomb Ferromagnet CrI 3 .
Phys Rev X
; 8(4)2018 Dec.
Article
em En
| MEDLINE
| ID: mdl-38915421
ABSTRACT
In two-dimensional honeycomb ferromagnets, bosonic magnon quasiparticles (spin waves) may either behave as massless Dirac fermions or form topologically protected edge states. The key ingredient defining their nature is the next-nearest-neighbor Dzyaloshinskii-Moriya interaction that breaks the inversion symmetry of the lattice and discriminates chirality of the associated spin-wave excitations. Using inelastic neutron scattering, we find that spin waves of the insulating honeycomb ferromagnet CrI 3 ( T C = 61 K ) have two distinctive bands of ferromagnetic excitations separated by a â¼4 meV gap at the Dirac points. These results can only be understood by considering a Heisenberg Hamiltonian with Dzyaloshinskii-Moriya interaction, thus providing experimental evidence that spin waves in CrI 3 can have robust topological properties potentially useful for dissipationless spintronic applications.
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MEDLINE
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En
Ano de publicação:
2018
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Article