Abstract

The complex oxides have set the stage for some of the most intriguing phenomena found in condensed matter including high-temperature superconductivity, multiferroicity and many exotic forms of magnetism. In recent years, it has become possible to create heterostructures of different complex oxides in an atomic layer-by-layer manner. These structures often have properties that are distinct from those of their constituent materials, and could be used to tailor novel electronic and magnetic states. In my talk, I will focus on digital superlattices of (LaMnO3)p/(SrMnO3)q, where p, q are integers, and the La/Sr atoms are ordered in two-dimensional planes. LaMnO3 and SrMnO3 are both antiferromagnetic insulators. However, depending upon the choice of p and q, the superlattices show a wide range of properties, including a ferromagnetic metal, an antiferromagnet with an enhanced ordering (Néel) temperature and a delta-doped ferromagnet within an antiferromagnetic host. The ability to synthesize materials with single atomic layer precision also allows us to tailor single crystals with attributes such as artificially broken inversion symmetry, that may not be possible to realize in bulk samples. I will present an example of this and its consequences in quasi two-dimensional nickelates. The approaches presented here can be explored for a broad range of materials, and may have implications for fundamental science as well as applications.

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).