Identification of magnetic interactions and high-field quantum spin liquid in α-RuCl3

• Published in: Nature communications Vol. 12; no. 1; pp. 4007 - 11
• Main Authors: Li, Han, Zhang, Hao-Kai, Wang, Jiucai, Wu, Han-Qing, Gao, Yuan, Qu, Dai-Wei, Liu, Zheng-Xin, Gong, Shou-Shu, Li, Wei
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29.06.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/119/2795; 639/766/119/997; 639/766/119/999; Anisotropy; Entropy; Heat; Humanities and Social Sciences; Liquid phases; Low temperature; Magnetic anisotropy; Magnetic fields; multidisciplinary; NMR; Nuclear magnetic resonance; Physics; Ruthenium trichloride; Science; Science (multidisciplinary); Simulation; Specific heat; Spin liquid; Spin structure; Symmetry
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-24257-8

The frustrated magnet α -RuCl 3 constitutes a fascinating quantum material platform that harbors the intriguing Kitaev physics. However, a consensus on its intricate spin interactions and field-induced quantum phases has not been reached yet. Here we exploit multiple state-of-the-art many-body methods and determine the microscopic spin model that quantitatively explains major observations in α -RuCl 3 , including the zigzag order, double-peak specific heat, magnetic anisotropy, and the characteristic M-star dynamical spin structure, etc. According to our model simulations, the in-plane field drives the system into the polarized phase at about 7 T and a thermal fractionalization occurs at finite temperature, reconciling observations in different experiments. Under out-of-plane fields, the zigzag order is suppressed at 35 T, above which, and below a polarization field of 100 T level, there emerges a field-induced quantum spin liquid. The fractional entropy and algebraic low-temperature specific heat unveil the nature of a gapless spin liquid, which can be explored in high-field measurements on α -RuCl 3 . The nature of spin interactions and the field-induced quantum spin liquid phase in the Kitaev material α -RuCl 3 have been debated. Here, using a combination of many-body techniques, the authors derive an effective spin model that explains the majority of experimental findings and predicts a new quantum spin liquid phase in strong out-of-plane magnetic field.