Hybridization wave as the "hidden order" in URu ₂Si₂

A phenomenological model for the "hidden order" transition in the heavy-Fermion material URu₂Si₂ is introduced. The hidden order is identified as an incommensurate, momentum-carrying hybridization between the light hole band and the heavy electron band. This modulated hybridization appears after a Fano hybridization at higher temperatures takes place. We focus on the hybridization wave as the order parameter in URu ₂Si₂ and possibly other materials with similar band structures. The model is qualitatively consistent with numerous experimental results obtained from, e.g., neutron scattering and scanning tunneling microscopy. Specifically, we find a gaplike feature in the density of states and the appearance of features at an incommensurate vector Q ^*∼0.6π/a₀. Finally, the model allows us to make various predictions which are amenable to current experiments.