PERSPECTIVE: Emergent phases in rare earth nickelate heterostructures

The prediction of high $T_c$ superconductivity in layers of LaNiO$_3$ through orbital engineering has led to extensive research efforts over the last fifteen years. During this period, a plethora of thin films and heterostructures based rare-earth nickelate family with perovskite structure has been synthesized and explored. In this short perspective, we briefly review the complexity of bulk $RE$NiO$_3$, spotlighting several recent findings of emergent phenomena in heterostructures containing the interface between $RE$NiO$_3$ and another transition metal oxide. Finally, we outline potentially interesting future directions linked to time-domain dynamics to harness new Mott and topological phases in artificial structures of $RE$NiO$_3$.