October 11, 2021
Scientific Achievement
It is shown that normally invisible quadrupolar spin fluctuations dominate the excitation spectrum of ordered FeI2.
![](http://swc.tennessee.edu/wp-content/uploads/2022/03/quadrapolar_highlight.png)
Significance and Impact
The work shows how the effect of spin-orbit coupling can hybridize dipolar and quadrupolar fluctuations, leading to unexpected quantum excitations despite the classical ground-state, a result that may be applicable to a range of other materials with hitherto unexplained multipolar excitations.
Research Details
- Successful comparison with SU(3) generalized spin-wave theory explained the observed neutron scattering and allowed extraction of most details of the complex magnetic Hamiltonian of FeI2.
- Anisotropic exchange interactions are identified as the mechanism behind the dipolar-quadrupolar hybridization, solving a 40+ year old puzzle.
Related Publication: Bai, X. et. al. (2021). Hybridized Quadrupolar Excitations in the Spin-anisotropic Frustrated Magnet FeI2. Nature Physics, 17, 467-472. https://doi.org/10.1038/s41567-020-01110-1