Quantum spin dynamics of the honeycomb magnet in high magnetic fields
Phys. Rev. B 112, 014455 – Published 31 July, 2025
DOI: https://doi.org/10.1103/dnpq-lnrm
Abstract
We present terahertz spectroscopic measurements of quantum spin dynamics in the honeycomb magnet as a function of temperature, polarization and in an external magnetic field applied in the honeycomb plane. Magnetic excitations are resolved below the magnetic ordering temperature of K. In the applied magnetic field, we reveal characteristic field dependence not only for the magnetic excitations observed at zero field but also a rich set of modes emerging in finite fields. The observed magnetic excitations exhibit clear dependence on the terahertz polarization and characteristic features at field-induced phase transitions consistent with our high-field magnetization data. We cannot evidently resolve a continuumlike feature, even when the long-range magnetic order is presumably suppressed in the strong magnetic field, indicating that a Kitaev-type interaction, if existing, is subleading in this compound.
