The complex oxides have set the stage for some of the most intriguing phenomena, including hightemperature superconductivity, multiferroicity and many exotic forms of magnetism. In recent years it has become possible to create artificial heterostructures where oxides with diverse ground states can be brought together at atomically sharp interfaces. Due to interfacial charge transfer, strain and proximity effects, these heterostructures may give rise to new kinds of interactions and collective

states with properties that are very different from those of their constituents. I will present our work on superlattices comprising manganites and nickelates in this light. In particular, I will discuss how metalinsulator transitions, enhanced magnetic ordering temperatures and delta-doped analogs of magnetism can be realized by interfacial charge transfer in ordered superlattices grown using oxide- MBE. The ability to synthesize materials in an atomic layer-by-layer manner also allows us to tailor single crystals with attributes such as artificially broken inversion symmetry, in a manner that may not be possible using bulk synthesis techniques. I will present an example of this in the context of nickelates. The approaches presented here can be explored for a broad range of materials, and may lead to phenomena that may be interesting from a variety of perspectives.

References:
[1] "Enhanced ordering temperatures in antiferromagnetic manganite superlattices", S. May et al., Nature Materials 8, 892 (2009).
[2] “Delta Doping of Ferromagnetism in Antiferromagnetic Manganite Superlattices”, T. Santos et al., Phys. Rev. Lett. 107, 167202 (2011).
[3] “Charge transfer and interfacial magnetism in (LaNiO3)n/(LaMnO3)2 superlattices”, Hoffman, J., et al., Phys. Rev. B 88, 144411 (2013).