Kitaev interactions, arising from the interplay of frustration and bond anisotropy, can lead to strong quantum fluctuations and, in an ideal case, to a quantum-spin-liquid state. However, in many nonideal materials, spurious non-Kitaev interactions typically promote a zigzag antiferromagnetic order in the d-orbital transition metal compounds. By combining neutron scattering with muon-spin rotation and relaxation techniques, we provide new insights into the exotic properties of Na2Co2TeO6, a candidate Kitaev material. Below TN, the zero-field muon-spin relaxation rate becomes almost constant (at 0.45 us-1). We attribute this temperature-independent muon-spin relaxation rate to the strong quantum fluctuations, as well as to the frustrated Kitaev interactions. As the magnetic field increases, neutron scattering data indicate a much broader spin-wave-excitation gap at the K-point. Therefore, quantum fluctuations seem not only robust, but are even enhanced by the applied magnetic field. Our findings provide valuable hints for understanding the onset of the quantum-spin-liquid state in Kitaev materials.
@article{arxiv.2312.06284,
title = {Static magnetic order with strong quantum fluctuations in spin-1/2 honeycomb magnet Na2Co2TeO6},
author = {Gaoting Lin and Jinlong Jiao and Xiyang Li and Mingfang Shu and Oksana Zaharko and Toni Shiroka and Tao Hong and Alexander I. Kolesnikov and Guochu Deng and Sarah Dunsiger and Haidong Zhou and Tian Shang and Jie Ma},
journal= {arXiv preprint arXiv:2312.06284},
year = {2023}
}