# $\mu$SR Insight into the Impurity Problem in Quantum Kagome Antiferromagnets

Authors
Type
Preprint
Publication Date
Apr 11, 2016
Submission Date
Apr 11, 2016
Identifiers
arXiv ID: 1604.02916
Source
arXiv
Impurities, which are inherently present in any real material, may play an important role in the magnetism of frustrated spin systems with spin-liquid ground states. We address the impurity issue in quantum kagome antiferromagnets by investigating ZnCu$_3$(OH)$_6$SO$_4$ (Zn-brochantite) by means of muon spin spectroscopy. We show that muons couple to the impurity magnetism, originating from Cu-Zn intersite disorder, and that the impurities are highly correlated with the kagome spins, allowing us to probe the intrinsic kagome physics via a Kondo-like effect. The low-temperature plateau in local susceptibility identifies the spin-liquid ground state as being gapless. The corresponding spin fluctuations exhibit an unconventional spectral density and an intriguing field dependence.