We report 17O NMR measurements in the S=1/2 Cu2+ kagome antiferromagnet Herbertsmithite ZnCu3(OH)6Cl2 down to 45mK in magnetic fields ranging from 2T to 12T. While Herbertsmithite displays a gapless spin-liquid behavior in zero field, we uncover an instability toward a spin-solid phase at sub-kelvin temperature induced by an applied magnetic field. The latter phase shows largely suppressed moments ≲0.1\muB and gapped excitations. The H-T phase diagram suggests the existence of a quantum critical point at the small but finite magnetic field mu0 Hc=1.55(25)T. We discuss this finding in light of the perturbative Dzyaloshinskii-Moriya interaction which was theoretically proposed to sustain a quantum critical regime for the quantum kagome Heisenberg antiferromagnet model.
@article{arxiv.1109.1316,
title = {Field-Induced Freezing of a Quantum Spin Liquid on the Kagome Lattice},
author = {M. Jeong and F. Bert and P. Mendels and F. Duc and J. C. Trombe and M. A. de Vries and A. Harrison},
journal= {arXiv preprint arXiv:1109.1316},
year = {2013}
}
Comments
One link added for supplemental materials. Published in : Phys. Rev. Lett. 107, 237201 (2011)