Alternating-bias assisted annealing of amorphous oxide tunnel junctions
Superconducting quantum bits (qubits) rely on ultra-thin, amorphous oxide tunneling barriers that can have significant inhomogeneities and defects as grown. This can result in relatively large uncertainties and deleterious effects in the circuits, limiting the scalability. Finding a robust solution to the junction reproducibility problem has been a long-standing goal in the field. Here, we demonstrate a transformational technique for controllably tuning the electrical properties of aluminum-oxide tunnel junctions. This is accomplished using a low-voltage, alternating-bias applied individually to the tunnel junctions, with which resistance tuning by more than 70% can be achieved. The data indicates an improvement of coherence and reduction of two-level system defects. Transmission electron microscopy shows that the treated junctions are predominantly amorphous, albeit with a more uniform distribution of alumina coordination across the barrier. This technique is expected to be useful for other devices based on ionic amorphous materials.
- Research Organization:
- Ames Laboratory (AMES), Ames, IA (United States); Iowa State U.; Rigetti Computing
- Sponsoring Organization:
- US Department of Energy; USDOE Office of Science (SC)
- Grant/Contract Number:
- 89243024CSC000002; AC02-07CH11358; AC02-07CH11359
- OSTI ID:
- 2323462
- Report Number(s):
- FERMILAB-PUB-24-0047-SQMS-V; IS-J--11,414; oai:inspirehep.net:2747393; arXiv:2401.07415
- Journal Information:
- Commun.Mater., Journal Name: Commun.Mater. Vol. 5
- Country of Publication:
- United States
- Language:
- English
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