NMR evidence of spinon localization in kagome antiferromagnet YCu$_3$(OH)$_6$Br$_2$[Br$_{1-x}$(OH)$_x$]
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arXiv
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| Main Authors: | , , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866910365450764288 |
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| author | Li, Shuo Cui, Yi Zeng, Zhenyuan Wang, Yue Hu, Ze Liu, Jie Li, Cong Xu, Xiaoyu Chen, Ying Liu, Zhengxin Li, Shiliang Yu, Weiqiang |
| author_facet | Li, Shuo Cui, Yi Zeng, Zhenyuan Wang, Yue Hu, Ze Liu, Jie Li, Cong Xu, Xiaoyu Chen, Ying Liu, Zhengxin Li, Shiliang Yu, Weiqiang |
| contents | We performed nuclear magnetic resonance studies on a kagome antiferromagnet YCu$_3$(OH)$_6$Br$_2$[Br$_{1-x}$(OH)$_{x}$]. No significant NMR spectral broadening is found in the Br center peak from 1 K down to 0.05 K, indicating absence of static antiferromagnetic ordering. In contrast to signatures of dominant 2D kagome antiferromagnetic fluctuations at temperature above 30 K, both the Knight shift $K_{\rm{n}}$ and the spin-lattice relaxation rate $1/T_{1}$ increase when the sample is cooled from 30 K to 8 K, which can be attributed to the scattering of spin excitations by strong non-magnetic impurities. Unusually, a hump is observed in $K_{\rm{n}}$ and $1/T_{2}$ close to 2 K (far below the exchange energy), which indicates the existence of excitations with a large density of states close to zero energy. These phenomena are reproduced by a mean-field simulation of Heisenberg model with bond-dependent exchange interactions, where the sign fluctuations in the spinon kinetic terms caused by impurities result in localization of spinons and an almost flat band close to the Fermi energy. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2402_05693 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | NMR evidence of spinon localization in kagome antiferromagnet YCu$_3$(OH)$_6$Br$_2$[Br$_{1-x}$(OH)$_x$] Li, Shuo Cui, Yi Zeng, Zhenyuan Wang, Yue Hu, Ze Liu, Jie Li, Cong Xu, Xiaoyu Chen, Ying Liu, Zhengxin Li, Shiliang Yu, Weiqiang Strongly Correlated Electrons We performed nuclear magnetic resonance studies on a kagome antiferromagnet YCu$_3$(OH)$_6$Br$_2$[Br$_{1-x}$(OH)$_{x}$]. No significant NMR spectral broadening is found in the Br center peak from 1 K down to 0.05 K, indicating absence of static antiferromagnetic ordering. In contrast to signatures of dominant 2D kagome antiferromagnetic fluctuations at temperature above 30 K, both the Knight shift $K_{\rm{n}}$ and the spin-lattice relaxation rate $1/T_{1}$ increase when the sample is cooled from 30 K to 8 K, which can be attributed to the scattering of spin excitations by strong non-magnetic impurities. Unusually, a hump is observed in $K_{\rm{n}}$ and $1/T_{2}$ close to 2 K (far below the exchange energy), which indicates the existence of excitations with a large density of states close to zero energy. These phenomena are reproduced by a mean-field simulation of Heisenberg model with bond-dependent exchange interactions, where the sign fluctuations in the spinon kinetic terms caused by impurities result in localization of spinons and an almost flat band close to the Fermi energy. |
| title | NMR evidence of spinon localization in kagome antiferromagnet YCu$_3$(OH)$_6$Br$_2$[Br$_{1-x}$(OH)$_x$] |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2402.05693 |