Anisotropic magnetic excitations from single-chirality antiferromagnetic state in Ca-kapellasite
We present a ^{35}Cl NMR study for the spin S=1/2 perfect kagome antiferromagnet Ca-kapellasite [CaCu_{3}(OH)_{6}Cl_{2}·0.6H_{2}O] with a magnetic transition at T^{*}=7.2K. The static magnetic structure in the ground state has been determined to be a chirality-ordered Q=0 state, which is selected by...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2020-06-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.2.023269 |
| Summary: | We present a ^{35}Cl NMR study for the spin S=1/2 perfect kagome antiferromagnet Ca-kapellasite [CaCu_{3}(OH)_{6}Cl_{2}·0.6H_{2}O] with a magnetic transition at T^{*}=7.2K. The static magnetic structure in the ground state has been determined to be a chirality-ordered Q=0 state, which is selected by a finite Dzyaloshinskii-Moriya interaction. The low-energy magnetic excitations in the ordered state are investigated by a nuclear spin-lattice relaxation rate measurement. We detect a weakly temperature-dependent contribution in the magnetic fluctuations perpendicular to the kagome plane in addition to the dispersive spin-wave contribution in the kagome plane. The low-energy magnetic excitations from the coplanar spin structure are attributed to the zero mode originating from the flat band in this kagome antiferromagnet. |
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| ISSN: | 2643-1564 |