Digital Synthesis: A Pathway to New Materials in the Complex Oxides
The complex oxides have set the stage for some of the most striking phenomena in condensed matter, including high-temperature superconductivity and colossal magnetoresistance. These collective properties emerge as a result of strong correlations between the various degrees of freedom within these materials. In recent years, it has become possible to create artificial structures where complex oxides with diverse ground states are brought together at atomically sharp interfaces, in a manner similar to what is routinely done with semiconductors. Such structures may give rise to collective states that are distinct from those found in the constituent materials.
I will present our work on ‘digital’ superlattices of (LaMnO3)p/(SrMnO3)q, where p,q are integers, and the La/Sr cations are ordered in 2-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 in an antiferromagnetic host. Time permitting, I will also discuss some recent results in other materials systems that we are currently exploring.