The Department of Physics Colloquium

 Series Presents

Dr. Ryan Comes

“MBE-grown 4d and 5d Oxide Heterostructures for Electronic and Quantum Systems”

Complex oxides comprised of transition metal cations exhibit a host of intriguing properties for new technologies that can be tuned by the choice of ions from the 3d, 4d, and 5d blocks of the periodic table. Perovskite oxides with the chemical formula ABO₃ have some of the richest behavior, where they can exhibit ferroelectricity, ferromagnetism, or superconductivity depending on the choice of B-site metal ion. This combination of properties in a single class of materials offers rich opportunities for engineering of unusual combinations of behavior through the design of multi-layer thin films. Using molecular beam epitaxy (MBE), we are able to control these materials down to the atomic level so that interfaces between two different materials can be tuned to produce desirable properties for electronic, energy, and quantum applications.

In this talk I will show how we can optimize electronic properties using in situ techniques to understand the film growth process and resulting functional properties. I will show how hybrid MBE can enable synthesis of hard to grow materials using metalorganic precursors, including SrNbO₃, SrTaO₃, SrIrO₃, and SrHfO₃. I will introduce how we have employed hybrid MBE and in situ X-ray photoelectron spectroscopy (XPS) plus density functional theory to predict charge transfer in BaSnO₃/SrNbO₃ heterostructures and related materials. I will also discuss our ongoing work on SrIrO₃ heterostructures, which have the potential for emergent superconductivity and topological magnetic phases.