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Thermal Evolution of Dirac Magnons in the Honeycomb Ferromagnet CrBr$_3$
- Source :
- Physical Review Letters 129, 127201 (2022)
- Publication Year :
- 2022
-
Abstract
- CrBr$_3$ is an excellent realization of the two-dimensional honeycomb ferromagnet, which offers a bosonic equivalent of graphene with Dirac magnons and topological character. We perform inelastic neutron scattering (INS) measurements using state-of-the-art instrumentation to update 50-year-old data, thereby enabling a definitive comparison both with recent experimental claims of a significant gap at the Dirac point and with theoretical predictions for thermal magnon renormalization. We demonstrate that CrBr$_3$ has next-neighbor $J_2$ and $J_3$ interactions approximately 5\% of $J_1$, an ideal Dirac magnon dispersion at the K point, and the associated signature of isospin winding. The magnon lifetime and the thermal band renormalization show the universal $T^2$ evolution expected from an interacting spin-wave treatment, but the measured dispersion lacks the predicted van Hove features, highlighting the need for a deeper theoretical analysis.
- Subjects :
- Condensed Matter - Strongly Correlated Electrons
Subjects
Details
- Database :
- arXiv
- Journal :
- Physical Review Letters 129, 127201 (2022)
- Publication Type :
- Report
- Accession number :
- edsarx.2204.11355
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevLett.129.127201