Control of hidden ground-state order in NdNi O 3 superlattices

The fascinating behavior of transition metal oxides can change dramatically when they are scaled down to atomic-size dimensions; however, understanding the emergent properties is a major challenge. In this paper, the authors observe the evolution of multiple phase transitions as the thickness is reduced from bulk to the atomic layer limit in NdNiO${}_{3}$ superlattices. Their measurements demonstrate a separation of the insulating phase from magnetic and charge-ordered phases, which coexist in the bulk, and the emergence of a hidden, unordered insulating phase for a single atomic layer. Modeling shows that the phase manipulation uniquely takes advantage of the effects of 2D confinement and symmetry-breaking at the interface.