2018/07/31 by Lebing Chen, Jae-Ho Chung, Bin Gao +5 · 5 citations
Materials Science · Physics and Astronomy · #2D Materials and Applications #Advanced Condensed Matter Physics #Fermion #Ferromagnetism #Hamiltonian (control theory) #Lattice (music) #Magnon #Quasiparticle #Spin wave #Spintronics #Topological Materials and Phenomena #Topological insulator #cond-mat.str-el
paper · pdf · doi:10.1103/physrevx.8.041028
published as Phys. Rev. X 8, 041028 (2018) · 6 pages, 4 figures with supplemental information, accepted for publication in Phys. Rev. X
openalex created_date 2018/08/03 · arxiv created 2018/10/30 · openalex publication_date 2018/11/14 · arxiv updated 2018/11/21 · openalex updated_date 2026/08/06
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 4 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.