We present terahertz spectroscopic measurements of quantum spin dynamics in the honeycomb magnet K2Co2TeO6 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 TN = 12 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.
@article{arxiv.2503.07174,
title = {Quantum spin dynamics of the honeycomb magnet K$_2$Co$_2$TeO$_6$ in high magnetic fields},
author = {Patrick Pilch and Laur Peedu and Urmas Nagel and Toomas Rõõm and Changqing Zhu and Yurii Skourski and Xianghan Xu and Robert J. Cava and Zhe Wang},
journal= {arXiv preprint arXiv:2503.07174},
year = {2025}
}