CAREER: Atomic-scale Josephson Spectroscopic Imaging of Unconventional and Non-reciprocal Superconductivity

About This Grant

Non-technical Abstract: A good example of directional response of a system can be found in a semiconductor diode, where current flows more easily in one direction than the other. Similar behavior in superconductors can lead to applications in next-generation superconducting and quantum technologies. This project investigates superconducting materials exhibiting such effects at the atomic scale, with the objective of providing insights into superconductivity and its underlying mechanisms. The research activities are integrated with a research-centered educational plan for students and researchers across various disciplines, emphasizing critical thinking and the development of technical expertise. To broaden and sustain educational impact, the project includes a “STEM Teachers Residency” program, through which middle school teachers participate directly in research and co-develop innovative curriculum materials for nationwide dissemination. Public and scientific outreach efforts include the design and construction of educational demonstration setups for use in classrooms, research facilities, and the Children’s Museum of South Bend. Technical Abstract: The superconducting diode effect is a manifestation of non-reciprocal superconductivity. It typically requires simultaneous breaking of both inversion and time-reversal symmetries. The ability to detect and tune this effect not only offers a path to discovering symmetry-breaking unconventional superconductivity, but also enables immediate applications in superconducting electronics, spintronics, and quantum technologies. The research team leverages scanned Josephson tunneling microscopy to investigate the superconducting diode effect at the atomic scale and cryogenic temperatures. The goal is to reveal and control local intrinsic symmetry-breaking patterns in non-reciprocal superconductors that remain undetectable via macroscopic devices or optical measurements, due to factors such as crystal twinning and surface degradation. The project aims to derive signatures of the superconducting diode effect in atomic-scale Josephson junctions and to develop a new imaging modality that enables flexible choices of junction materials and interlayer twistability. Interdisciplinary education and outreach activities targeting students, middle school teachers, and the general public are fully integrated into the project, along with comprehensive training for students and postdoctoral researchers in numerical modeling, experimental techniques, and advanced instrumentation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.