Quantum materials: design and characterization
Functional oxides that exhibit exciting and potentially useful properties including superconductivity, ferroelectricity, piezoelectricity, and magnetism are being intensively studied. These properties, together with the possibility of tuning them through strain, chemical doping or the application of external fields, make such functional oxides suitable for use in microelectromechanical systems (MEMS), transistors, and field effect devices. Significant progress in the growth of atomic-scale multilayers opens exciting opportunities in the design of materials with novel properties.
In the first part of my talk I will present an example of quantum many-body systems: cuprates. In these materials, carrier doping of the Mott insulating parent state is necessary to realize superconductivity as well as a number of other exotic states involving charge or spin density waves. So far, cation substitution is the primary method for doping carriers into these compounds, and is the only known method for electron doping in these materials. I will demonstrate electron doping without cation substitution in epitaxially stabilized thin films of La2CuO4 grown via molecular-beam epitaxy. Angle-resolved photoemission spectroscopy has been used to directly measure their electronic structure. In the second part of my talk I will show the new MBE facility at Stanford with related research topics that I am investigating.