The Kitaev model on a honeycomb lattice predicts a paradigmatic quantum spin liquid (QSL) exhibiting Majorana Fermion excitations. The insight that Kitaev physics might be realized in practice has stimulated investigations of candidate materials, recently including alpha-RuCl3. In all the systems studied to date, non-Kitaev interactions induce magnetic order at low temperature. However, in-plane magnetic fields of roughly 8 Tesla suppress the long-range magnetic order in alpha-RuCl3 raising the intriguing possibility of a field-induced QSL exhibiting non-Abelian quasiparticle excitations. Here we present inelastic neutron scattering in alpha-RuCl3 in an applied magnetic field. At a field of 8 Tesla, the spin waves characteristic of the ordered state vanish throughout the Brillouin zone. The remaining single dominant feature of the response is a broad continuum centered at the Gamma point, previously identified as a signature of fractionalized excitations. This provides compelling evidence that a field-induced QSL state has been achieved.
@article{arxiv.1706.07003,
title = {Excitations in the field-induced quantum spin liquid state of alpha-RuCl3},
author = {A. Banerjee and P. Lampen-Kelley and J. Knolle and C. Balz and A. A. Aczel and B. Winn and Y. Liu and D. Pajerowski and J. -Q. Yan and C. A. Bridges and A. T. Savici and B. C. Chakoumakos and M. D. Lumsden and D. A. Tennant and R. Moessner and D. G. Mandrus and S. E. Nagler},
journal= {arXiv preprint arXiv:1706.07003},
year = {2018}
}