Microscopic properties of the 'pinwheel' kagome compound Rb_2Cu_3SnF_{12}
| Autor: | Grbić, M. S., Krämer, S., Berthier, C., Trousselet, F., Cépas, O., Tanaka, H., Horvatić, M. |
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| Rok vydání: | 2012 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.110.247203 |
| Popis: | Using $^{63,65}$Cu nuclear magnetic resonance (NMR) in magnetic fields up to 30 T we study the microscopic properties of the 12-site valence-bond-solid ground state in the "pinwheel" kagome compound Rb$_2$Cu$_3$SnF$_{12}$. We find that the ground state is characterized by a strong transverse staggered spin polarization whose temperature and field dependence points to a mixing of the singlet and triplet states. This is further corroborated by the field dependence of the gap $\Delta (H)$, which has a level anticrossing with a large minimum gap value of $\approx \Delta (0)/2$, with no evidence of a phase transition down to 1.5\,K. By the exact diagonalization of small clusters, we show that the observed anticrossing is mainly due to staggered tilts of the $g$-tensors defined by the crystal structure, and reveal symmetry properties of the low-energy excitation spectrum compatible with the absence of level crossing. Comment: version 2: 5 pages, 4 figures + in Supplementary material: 3 pages, 2 figures. Accepted for publication in Physical Review Letters |
| Databáze: | arXiv |
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