A Joint ALS/Foundry Seminar
Seminar Date: Tuesday, November 10, 2026
Time: 11:00 AM PT
Location: 67-3111 & Zoom
Talk Title: Identifying Decoherence Mechanisms in Superconducting Qubits through Advanced Materials Characterization
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Abstract:
Although superconducting qubits have emerged as a leading technology platform for quantum computing through large improvements in device coherence times and gate fidelity in recent years, the presence of defects and impurities at the interfaces and surfaces in the constituent materials continue to limit performance and serve as a critical barrier in achieving scalable quantum systems. Understanding and eliminating these sources of quantum decoherence in superconducting qubit devices requires dedicated studies aimed at establishing robust structure-property relationships that will enable researchers to target and eliminate defects strategically. As part of the Superconducting Quantum Materials and Systems (SQMS) center, we have extensively employed state-of-the-art materials characterization techniques, including scanning/transmission electron microscopy, secondary ion mass spectrometry, atom probe tomography, x-ray diffraction, and x-ray photoelectron spectroscopy in conjunction with device measurements to elucidate such relationships. In this talk, I will discuss some of our recent findings, including identifying atomic defects contributing microwave loss in surface oxides, linking low temperature precipitates to device performance, and understanding materials-level sources of performance variations. By applying these insights, we have been able to strategically develop and implement mitigation strategies for reproducible fabrication of high coherence superconducting qubits.
Bio:
Akshay Murthy is an associate scientist and group leader at Fermilab. As part of the SQMS Center, he serves as the leader for the materials focus area, which includes groups focused on nanofabrication, structural/chemical characterization, superconducting characterization, and microwave measurements. At Fermilab, his research group composed of graduate students, postdoctoral researchers, and engineers focuses on applying a wide variety of materials characterization techniques to improve the quality and performance of superconducting and spin qubits as well as superconducting resonators. This involves the use of electron microscopy and time-of-flight secondary ion mass spectrometry to identify potential sources of quantum decoherence and loss in these systems.
Akshay received his Ph.D. in Materials Science and Engineering from Northwestern University in 2020 and his B.S. in Materials Science and Engineering in 2015 from the University of Illinois at Urbana-Champaign. He was originally hired as a postdoctoral research associate at Fermilab in 2021.
