Abstract
We use neutron scattering to show that ferromagnetic (FM) phase transition in the two-dimensional (2D) honeycomb lattice CrI3 is a weakly first order transition and controlled by spin-orbit coupling (SOC) induced magnetic anisotropy, instead of magnetic exchange coupling as in a conventional ferromagnet. With increasing temperature, the magnitude of magnetic anisotropy, seen as a spin gap at the Brillouin zone center, decreases in a power law fashion and vanishes at TC, while the in-plane and c-axis spin-wave stiffnesses associated with magnetic exchange couplings remain robust at TC. We also compare parameter regimes where spin waves in CrI3 can be described by a Heisenberg Hamiltonian with Dzyaloshinskii-Moriya interaction or a Heisenberg-Kitaev Hamiltonian. These results suggest that the SOC induced magnetic anisotropy plays a dominant role in stabilizing the FM order in single layer 2D van der Waals ferromagnets.
Original language | English |
---|---|
Article number | 134418 |
Journal | Physical Review B |
Volume | 101 |
Issue number | 13 |
DOIs | |
Publication status | Published - 2020 Apr 1 |
Bibliographical note
Publisher Copyright:© 2020 American Physical Society.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics