μSR insight into the impurity problem in quantum kagome antiferromagnets

作者：Gomilsek, M.; Klanjsek, M.; Pregelj, M.; Luetkens, H.; Li, Y.; Zhang, Q. M.; Zorko, A.^*

来源：Physical Review B, 2016, 94(2): 024438.

DOI：10.1103/PhysRevB.94.024438

• LIQUID GROUND-STATE
• SPIN

Impurities, which are unavoidable in real materials, may play an important role in the magnetism of frustrated spin systems with a spin-liquid ground state. We address the impurity issue in quantum kagome antiferromagnets by investigating ZnCu3(OH)(6)SO4 (Zn-brochantite) by means of muon spin spectroscopy. We show that muons dominantly couple to impurities, originating from Cu-Zn intersite disorder, and that the impurity spins are highly correlated with the kagome spins, allowing us to probe the host kagome physics via a Kondo-like effect. The low-temperature plateau in the impurity susceptibility suggests that the kagome spin-liquid ground state is gapless. The corresponding spin fluctuations exhibit an unconventional spectral density and a nontrivial field dependence.

• 出版日期2016-7-29
• 单位中国人民大学