We performed 23Na NMR measurements on a single-domain crystal of the Kitaev material Na3Co2SbO6, with magnetic field applied along the crystalline a axis. A positive Curie-Weiss constant is obtained from the NMR Knight shift, which suggests the existence of ferromagnetic exchange couplings. The antiferromagnetic ordering is found to be suppressed at a field of 1.9 T. Inside the ordered phase, our data reveal two additional phase transitions. At 1.9 T, the spin-lattice relaxation rate 1/23T1 establishes a quantum critical behavior at high temperatures. However, at low temperatures, a gapped behavior is observed at the critical field, which suggests a weakly first-order transition instead and a possible field-induced quantum spin liquid. Our results reveal complex microscopic interactions in the system, which may help to search for possible quantum spin liquids.
@article{arxiv.2401.12448,
title = {Field-induced phase transitions and quantum criticality in a honeycomb antiferromagnet Na3Co2SbO6},
author = {Ze Hu and Yue Chen and Yi Cui and Shuo Li and Cong Li and Xiaoyu Xu and Ying Chen and Xintong Li and Yuchen Gu and Rong Yu and Rui Zhou and Yuan Li and Weiqiang Yu},
journal= {arXiv preprint arXiv:2401.12448},
year = {2024}
}