Speaker: Sébastien Burdin, University of Bordeaux, France
Abstract: We have shown that near a Kondo breakdown critical point, a spin liquid with spatial modulations is likely to be formed. Unlike its uniform counterpart, we find that this occurs via a second order phase transition. The amount of entropy quenched when this ordering is manifest is of the same magnitude as for an antiferromagnet. Moreover, these two states are in direct competition with each other, and at low temperatures they are separated by a first order phase transition. This suggests that the modulated spin liquid is indeed a viable candidate for the unique phase of matter which is observed in the hidden order phase of URu2Si2. We investigate the modulated spin liquid proposal taking full account of the tetragonal-body-centered lattice structure which characterizes URu2Si2. We find that the physical quantities predicted from the model are in very good qualitative and quantitative agreement with recent experiments, including thermodynamic properties, inelastic neutron scattering, and Fermi surface measurements. We also present an overview of other f-electron compounds where similar phases have been observed.
C. Pepin, M.R. Norman, S. Burdin, and A. Ferraz, Phys. Rev. Lett. 106, 106601 (2011)
C. Thomas, S. Burdin, C. Pepin, and A. Ferraz, in preparation.