A team of Foundry staff and industry users have developed a new superconducting electron source fabricated from a monocrystalline niobium wire with a tip radius of just 1.5nm.
Significance and Impact
The new nanotip is so small that only one quantum energy level can fit in it and produces an energy distribution 20 times smaller than conventional sources and maintaining high brightness. It may enable new fields in electron-based imaging and analysis and facilitate research in quantum information science.
- The team used electrochemical etching, focused ion beam milling, and thermal annealing techniques to fabricate the nano-tip. During field emission, the tip was cooled to a superconducting temperature of ~6K, and energy and brightness were analyzed.
- The resulting beam has a narrow energy spread and retains a small emission angle and high intensity.
- The team also created a custom tool to characterize the nanotip without removing it from a high-vacuum environment.
C.W. Johnson, A.K. Schmid, M. Markos, R. Ropke, N. Kerker, E.K. Wong, D.F. Ogletree, A.M. Minor, A. Stibor. Phys. Rev. Lett. 129, 244802 (2022) DOI: 10.1103/PhysRevLett.129.244802
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