2019/02/28 by Inhee Lee, Franz Utermohlen, Franz G. Utermohlen +8 · 1 citation
Engineering · Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Anisotropy #Condensed matter physics #Ferromagnetic resonance #Ferromagnetism #Heisenberg model #Magnetic field #Magnetism #Magnetization #Multiferroics and related materials #Perovskite Materials and Applications #Physics #Quantum mechanics #Spin (aerodynamics) #Spin wave #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.124.017201
published as Phys. Rev. Lett. 124, 017201 (2020) · 5 pages, 4 figures
openalex created_date 2019/02/21 · arxiv created 2019/11/18 · openalex publication_date 2020/01/02 · arxiv updated 2020/01/07 · openalex updated_date 2026/08/06
We lay the foundation for determining the microscopic spin interactions in two-dimensional (2D) ferromagnets by combining angle-dependent ferromagnetic resonance (FMR) experiments on high quality CrI3 single crystals with theoretical modeling based on symmetries. We discover that the Kitaev interaction is the strongest in this material with K\ensuremath∼\ensuremath-5.2 meV, 25 times larger than the Heisenberg exchange J\ensuremath∼\ensuremath-0.2 meV, and responsible for opening the \ensuremath∼5 meV gap at the Dirac points in the spin-wave dispersion. Furthermore, we find that the symmetric off-diagonal anisotropy \mathrm\ensuremathΓ\ensuremath∼\ensuremath-67.5 \ensuremathμeV, though small, is crucial for opening a \ensuremath∼0.3 meV gap in the magnon spectrum at the zone center and stabilizing ferromagnetism in the 2D limit. The high resolution of the FMR data further reveals a \ensuremathμeV-scale quadrupolar contribution to the S=3/2 magnetism. Our identification of the underlying exchange anisotropies opens paths toward 2D ferromagnets with higher TC as well as magnetically frustrated quantum spin liquids based on Kitaev physics.