Abstract
The origin of magnetic flux noise in superconducting quantum interference devices with a power spectrum scaling as ( is frequency) has been a puzzle for over 20 years. This noise limits the decoherence time of superconducting qubits. A consensus has emerged that the noise arises from fluctuating spins of localized electrons with an areal density of . We show that, in the presence of potential disorder at the metal-insulator interface, some of the metal-induced gap states become localized and produce local moments. A modest level of disorder yields the observed areal density.
- Received 21 July 2009
DOI:https://doi.org/10.1103/PhysRevLett.103.197001
©2009 American Physical Society