At low temperatures, Tb2Ti2O7 enters a spin liquid state, despite expectations of magnetic order and/or a structural distortion. Using neutron scattering, we have discovered that in this spin liquid state an excited crystal field level is coupled to a transverse acoustic phonon, forming a hybrid excitation. Magnetic and phononlike branches with identical dispersion relations can be identified, and the hybridization vanishes in the paramagnetic state. We suggest that Tb2Ti2O7 is aptly named a "magnetoelastic spin liquid" and that the hybridization of the excitations suppresses both magnetic ordering and the structural distortion. The spin liquid phase of Tb2Ti2O7 can now be regarded as a Coulomb phase with propagating bosonic spin excitations.
@article{arxiv.1305.5405,
title = {Magnetoelastic excitations in the pyrochlore spin liquid Tb$_2$Ti$_2$O$_7$},
author = {T. Fennell and M. Kenzelmann and B. Roessli and H. Mutka and J. Ollivier and M. Ruminy and U. Stuhr and O. Zaharko and L. Bovo and A. Cervellino and M. K. Haas and R. J. Cava},
journal= {arXiv preprint arXiv:1305.5405},
year = {2014}
}
Comments
10 pages, 6 figures, supplementary information included