Can there be “Hidden Order” in transition metals?



We examine the conditions required to produce a combined spin and orbital density wave state such as that which has been proposed to describe the “Hidden Order” phase of URu2Si2. By using an idealized tight-binding model with only nearest-neighbor hopping processes, we search for factors that could stabilize “Hidden Order” phases in transition metals. It is found that strong anisotropy or reduced dimensionality may stabilize “Hidden Order” over spin-density wave phases. This suggests the possibility that the enigmatic pseudogap phases reported for the high-temperature ironpnictide superconductors may also be described by the Hund's rule “Hidden Order” mechanism.