Emergent Phenomena in Oxide Thin FilmsMaterials systems with many strongly interacting degrees of freedom can host some of the most exotic physical states known, ranging from superconductivity to topological phases.
One of the hallmarks of these quantum materials is the ability for a small perturbation to dramatically change the ground state. In thin films, the interface between two distinct materials forms a playground to engineer such emergent states. Specifically—and in contrast to bulk crystals—such an abrupt heterointerface can utilize the broken symmetry/reduced dimensionality inherent to the interface as well as induce chemical potential offsets, epitaxial strain and provide proximity to functional phases.
Work in the Mundy group will design, synthesize and probe such emergent phenomena in complex oxide thin films. Initial efforts will be particularly focused on using thin film epitaxy to construct metastable materials, with an emphasis on materials with strong spin frustration/exotic magnetic properties and novel superconductors.
FacilitiesOur primary synthesis tool will be dual chamber reactive oxide molecular-beam epitaxy instrument. Akin to "spray painting with atoms", molecular-beam epitaxy allows for the deposition of a single sheet of atoms and for complex structures to be constructed atomic-plane by atomic-plane. Our tool will be equipped with a total of 24 effusion cells, an e-beam reactor for low vapor pressure elements, a custom distilled ozone delivery system and automated sample transfer to provide rapid, high-throughput synthesis of a wide range of oxide thin films and heterostructures. The instrument is slated for installation summer 2018.
We will employ bulk and local probes for characterizing the structural, electronic and magnetic properties of our synthesized films. This will include a thin film x-ray diffractometer (slated for arrival 2018) and physical properties measurement system (slated for arrival 2019).
Our group will also use the aberration-corrected electron microscopy facility at the Harvard Center for Nanoscale systems. These tools will allow us to track local distortions in our buried interfaces to the picoscale. We will also use electron energy loss spectroscopy on the electron microscopy to probe the chemical composition, charge transfer and bonding atom-by-atom in our materials. We will correlate these local measurements to the macroscopic electronic and magnetic properties.
Finally, our group will make use of shared experimental facilities around the world including the NIST Center for Neutron Research and Advanced Light Source at Lawrence Berkeley National Laboratory to characterize the emergent properties in our synthesized materials.