title: Symmetry Reduction in the Quantum Kagome Antiferromagnet Herbertsmithite.
abstract: Employing complementary torque magnetometry and electron spin resonance on single crystals of herbertsmithite, the closest realization to date of a quantum kagome antiferromagnet featuring a spin-liquid ground state, we provide novel insight into different contributions to its magnetism. At low temperatures, two distinct types of defects with different magnetic couplings to the kagome spins are found. Surprisingly, their magnetic response contradicts the threefold symmetry of the ideal kagome lattice, suggesting the presence of a global structural distortion that may be related to the establishment of the spin-liquid ground state.
authors.affiliation: Jožef Stefan Institute, Jamova c. 39, SI-1000 Ljubljana, Slovenia.
authors.forename: A
authors.initials: A
authors.lastname: Zorko
authors.affiliation: Institute of Physics, Bijenička c. 46, HR-10000 Zagreb, Croatia.
authors.forename: M
authors.initials: M
authors.lastname: Herak
authors.affiliation: Jožef Stefan Institute, Jamova c. 39, SI-1000 Ljubljana, Slovenia.
authors.forename: M
authors.initials: M
authors.lastname: Gomilšek
authors.affiliation: National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA.
authors.forename: J
authors.initials: J
authors.lastname: van Tol
authors.affiliation: CNRS, Université de Bordeaux, ICMCB, UPR 9048, 87 Avenue du Dr. A. Schweitzer, 33608 Pessac Cedex, France.
authors.forename: M
authors.initials: M
authors.lastname: Velázquez
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Khuntia
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France.
authors.forename: F
authors.initials: F
authors.lastname: Bert
authors.affiliation: Laboratoire de Physique des Solides, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Mendels