Physikalisches Kolloquium

April 30, 2019 at 4 p.m. c.t. in HS KPH

Prof. Dr. Hans Jockers
Institut für Physik

Prof. Dr. Concettina Sfienti
Institut für Kernphysik

Spin, Charge, and Orbital Reconstructions in Complex Oxide Multilayers
Dr. Eva Benckiser (Max Planck Institute for Solid State Research, Stuttgart)

Transition-metal oxides with strong electron-electron correlations show a variety of interesting properties including metal-insulator transitions, different magnetic orders, and superconductivity. These phases are of technological interest, but often difficult to access because they only occur at very low temperatures, high external fields, or high pressures. Heterostructures offer promising new research approaches. Targeted interfacial reconstructions in epitaxial multilayers can stabilize novel phases that are not present in the bulk phase diagrams of the individual components. This is particularly relevant for multilayers with nanometre thin layers in which the properties are essentially governed by the interfacial reconstructions. Our research focuses on the investigation of such electronic reconstructions in the two-dimensional limit by means of x-ray spectroscopy. As a model system we have investigated perovskite-type nickelate heterostructures with composition RNiO3 (R = rare-earth ion). In my talk, I will present results of our studies on multilayers and will address layer-resolved orbital occupations, the unusual antiferromagnetic order and its interplay with the bond-order instability, and the feasibility of digital charge carrier doping.