Epitaxial nitride thin films for superconducting quantum circuits & the LQC
Abstract: This two-part presentation will first provide an overview of the Laboratory for Physical Sciences (LPS) Qubit Collaboratory (LQC), one of 13 Quantum Information Science Research Centers supporting the National Quantum Initiative. The LQC mission is to pursue research in disruptive qubit devices, contribute to the development of a quantum information science workforce, and develop deep partnerships in the QIS community. The LQC Qubits for Computing Foundry will also be highlighted. This program creates partnerships between research groups and state-of-the-art foundry services to ease the device fabrication burden necessary to conduct quantum computing hardware focused research.
In the second part, I will discuss my research focused on superconducting circuit components that are a necessity for the fabrication of high-fidelity superconducting qubits. Through a structure-first approach, Plasma Assisted Molecular Beam Epitaxy (PAMBE) is used to grow niobium titanium nitride alloys (NbxTi1-xN) and wide bandgap nitride (AlN) superconductors directly on sapphire wafers. This combination of nitride materials provides sufficient degrees of freedom that synthesis of an epitaxial Josephson junction may be possible. Growth results of NbxTi1-xN films on c-plane sapphire substrates, and initial trilayer NbTiN/AlN/NbTiN (superconductor-insulator-superconductor) Josephson junction structures on sapphire will be presented along with structural analysis and microwave measurements.
Bio: Dr. Richardson is the Deputy Director of the Laboratory for Physical Sciences (LPS) Qubit Collaboratory, a Research Scientist at LPS, and an Adjunct Professor in the Department of Materials Science and Engineering at the University of Maryland. He received his BS degree in engineering physics from the University of Maine, and MS and PhD degrees in materials science and engineering from Johns Hopkins University. He has authored papers and conference contributions in technical areas spanning epitaxial material design, growth, materials characterization, optoelectronic devices, and superconductor resonators. Richardson’s current research interests include molecular beam epitaxy of dissimilar materials and the materials science of quantum computing.