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arXiv · 2112.07199

Low-energy Spin Dynamics of Quantum Spin Liquid Candidate $NaYbSe_{2}$

Zheng Zhang·Jianshu Li·Mingtai Xie·Weizhen Zhuo·D. T. Adroja·Peter J. Baker·T. G. Perring·Anmin Zhang·Feng Jin·Jianting Ji·Xiaoqun Wang·Jie Ma·Qingming Zhang
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Abstract

The family of rare earth chalcogenides $ARECh_{2}$ (A = alkali or monovalent ions, RE = rare earth, and Ch = O, S, Se, and Te) appears as an inspiring playground for studying quantum spin liquids (QSL). The crucial low-energy spin dynamics remain to be uncovered. By employing muon spin relaxation ($\mu$SR) and zero-field (ZF) AC susceptibility down to 50 mK, we are able to identify the gapless QSL in $NaYbSe_{2}$, a representative member with an effective spin-1/2, and explore its unusual spin dynamics. The ZF $\mu$SR experiments unambiguously rule out spin ordering or freezing in $NaYbSe_{2}$ down to 50 mK, two orders of magnitude smaller than the exchange coupling energies. The spin relaxation rate, $\lambda$, approaches a constant below 0.3 K, indicating finite spin excitations featured by a gapless QSL ground state. This is consistently supported by our AC susceptibility measurements. The careful analysis of the longitudinal field (LF) $\mu$SR spectra reveals a strong spatial correlation and a temporal correlation in the spin-disordered ground state, highlighting the unique feature of spin entanglement in the QSL state. The observations allow us to establish an experimental H-T phase diagram. The study offers insight into the rich and exotic magnetism of the rare earth family.

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Zheng Zhang, Jianshu Li, Mingtai Xie, Weizhen Zhuo, D. T. Adroja, Peter J. Baker, T. G. Perring, Anmin Zhang, Feng Jin, Jianting Ji, Xiaoqun Wang, Jie Ma, Qingming Zhang. 2021-12-14. Low-energy Spin Dynamics of Quantum Spin Liquid Candidate $NaYbSe_{2}$. https://doi.org/10.1103/physrevb.106.085115

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