Na3Co2SbO6 is a potential Kitaev magnet with a monoclinic layered crystal structure. Recent investigations of the C3-symmetric sister compound Na2Co2TeO6 have uncovered a unique triple-q magnetic ground state, as opposed to a single-q (zigzag) one, prompting us to examine the influence of the reduced structural symmetry of Na3Co2SbO6 on its ground state. Neutron diffraction data obtained on a twin-free crystal reveal that the ground state remains a multi-q state, despite the system's strong in-plane anisotropy. This robustness of multi-q orders suggests that they are driven by a common mechanism in the honeycomb cobaltates, such as higher-order magnetic interactions. Spin-polarized neutron diffraction results show that the ordered moments are entirely in-plane, with each staggered component orthogonal to the propagating wave vector. The inferred ground state favors a so-called XXZ easy-plane anisotropic starting point for the microscopic model over a Kitaev one, and features unequal ordered moments reduced by strong quantum fluctuations.
@article{arxiv.2306.07175,
title = {Easy-plane multi-$\mathbf{q}$ magnetic ground state of Na$_3$Co$_2$SbO$_6$},
author = {Yuchen Gu and Xintong Li and Yue Chen and Kazuki Iida and Akiko Nakao and Koji Munakata and V. Ovidiu Garlea and Yangmu Li and Guochu Deng and I. A. Zaliznyak and J. M. Tranquada and Yuan Li},
journal= {arXiv preprint arXiv:2306.07175},
year = {2024}
}