Dynamic fingerprint of fractionalized excitations in single-crystalline Cu3Zn(OH)6FBr

Ying Fu; Miao-Ling Lin; Le Wang; Qiye Liu; Lianglong Huang; Wenrui Jiang; Zhanyang Hao; Cai Liu; Hu Zhang; Xingqiang Shi; Jun Zhang; Junfeng Dai; Dapeng Yu; Fei Ye; Patrick A Lee; Ping-Heng Tan; Jia-Wei Mei

doi:10.1038/s41467-021-23381-9

Dynamic fingerprint of fractionalized excitations in single-crystalline Cu₃Zn(OH)₆FBr

Nat Commun. 2021 May 24;12(1):3048. doi: 10.1038/s41467-021-23381-9.

Authors

Ying Fu^#¹, Miao-Ling Lin^#^{2

3}, Le Wang¹, Qiye Liu¹, Lianglong Huang¹, Wenrui Jiang¹, Zhanyang Hao¹, Cai Liu¹, Hu Zhang⁴, Xingqiang Shi⁴, Jun Zhang^{2

3

5}, Junfeng Dai¹, Dapeng Yu¹, Fei Ye^{1

6}, Patrick A Lee⁷, Ping-Heng Tan^{8

9

10}, Jia-Wei Mei^{11

12}

Affiliations

¹ Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen, China.
² State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China.
³ Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China.
⁴ College of Physics Science and Technology, Hebei University, Baoding, China.
⁵ Beijing Academy of Quantum Information Science, Beijing, China.
⁶ Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen, China.
⁷ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
⁸ State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China. [email protected].
⁹ Center of Materials Science and Optoelectronics Engineering & CAS Center of Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China. [email protected].
¹⁰ Beijing Academy of Quantum Information Science, Beijing, China. [email protected].
¹¹ Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen, China. [email protected].
¹² Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen, China. [email protected].

^# Contributed equally.

Abstract

Beyond the absence of long-range magnetic orders, the most prominent feature of the elusive quantum spin liquid (QSL) state is the existence of fractionalized spin excitations, i.e., spinons. When the system orders, the spin-wave excitation appears as the bound state of the spinon-antispinon pair. Although scarcely reported, a direct comparison between similar compounds illustrates the evolution from spinon to magnon. Here, we perform the Raman scattering on single crystals of two quantum kagome antiferromagnets, of which one is the kagome QSL candidate Cu₃Zn(OH)₆FBr, and another is an antiferromagnetically ordered compound EuCu₃(OH)₆Cl₃. In Cu₃Zn(OH)₆FBr, we identify a unique one spinon-antispinon pair component in the E_2g magnetic Raman continuum, providing strong evidence for deconfined spinon excitations. In contrast, a sharp magnon peak emerges from the one-pair spinon continuum in the E_g magnetic Raman response once EuCu₃(OH)₆Cl₃ undergoes the antiferromagnetic order transition. From the comparative Raman studies, we can regard the magnon mode as the spinon-antispinon bound state, and the spinon confinement drives the magnetic ordering.

Abstract

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