title: Microscopic properties of the pinwheel kagome compound Rb(2)Cu(3)SnF(12).
abstract: Using (63,65)Cu nuclear magnetic resonance 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 Δ(H), which has a level anticrossing with a large minimum gap value of ≈ Δ(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.
authors.affiliation: Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), UJF, UPS, and INSA, BP 166, 38042 Grenoble Cedex 9, France and Department of Physics, Faculty of Science, University of Zagreb, P.O. Box 331, HR-10002 Zagreb, Croatia.
authors.forename: M S
authors.initials: MS
authors.lastname: Grbić
authors.affiliation: Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), UJF, UPS, and INSA, BP 166, 38042 Grenoble Cedex 9, France.
authors.forename: S
authors.initials: S
authors.lastname: Krämer
authors.affiliation: Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), UJF, UPS, and INSA, BP 166, 38042 Grenoble Cedex 9, France.
authors.forename: C
authors.initials: C
authors.lastname: Berthier
authors.affiliation: Institut Néel, CNRS and Université Joseph Fourier, BP 166, 38042 Grenoble Cedex 9, France.
authors.forename: F
authors.initials: F
authors.lastname: Trousselet
authors.affiliation: Institut Néel, CNRS and Université Joseph Fourier, BP 166, 38042 Grenoble Cedex 9, France.
authors.forename: O
authors.initials: O
authors.lastname: Cépas
authors.affiliation: Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), UJF, UPS, and INSA, BP 166, 38042 Grenoble Cedex 9, France.
authors.forename: M
authors.initials: M
authors.lastname: Horvatić