In certain intriguing families of complex materials, unexpected physics arises due to the interplay of localised f-electrons, and itinerant d-electrons. Subtle changes in the balance of interactions can tip the ground state between dramatically different phases.
Traditionally, the ground state of these materials has been thought to fall into one of two possible categories: a ‘heavy’ state where the f-electrons ‘dissolve’ in the conduction sea of d-electrons, or a state in which the localised f-electrons order magnetically, independent of the conduction electron sea.
Our work has studied a variety of such materials, we find that in several cases this long held dichotomy is shattered and novel ground states are found to arise especially in the delicately balanced intermediate region.
