Complex oxides are a class of materials characterized by a variety of competing interactions that create a subtle balance to define the lowest energy state and lead to a wide diversity of intriguing properties ranging from high Tc superconductivity to exotic magnetism and orbital phenomena. By utilizing the bulk properties of these materials as a starting point, interfaces between different classes of complex oxides offer a unique opportunity to break the fundamental symmetries present in the bulk and alter the local environment. Utilizing our recent advances in oxide growth, we can now combine materials with distinct or even antagonistic order parameters to create new materials in the form of heterostructures with atomic layer precision. The broken lattice symmetry, strain, and altered chemical and electronic environments at the interfaces then provide a unique laboratory to manipulate this subtle balance and enable novel quantum states not attainable in bulk. Understanding of these phases however requires detailed microscopic studies of the heterostructure properties. In this talk I will summarize our work on unit-cell thin nickelate and cuprate-manganite heterostructures to illustrate uncovered principles of rational materials design and control of interactions by the interface.
Selected references for the talk:
J. Chakhalian et al, Science, v. 314, 1114, (2007). Jian Liu et al, Phys. Rev. B 83, 161102(R) (2011).
J. Freeland et al, Europhys. Letters, 96 (2011) 57004.
J. Chakhalian et al, Phys. Rev. Letters, 107 116805 (2011).
J. Chakhalian et al, Nature Materials 11, 92–94 (2012).