Low-frequency critical current fluctuations in Nb-AlOx-Nb trilayer Josephson junctions with diffused and epitaxially grown barriers
Abstract
Low-frequency 1/f noise and coupling to spurious two-level systems (TLS) limit the coherence time of superconducting flux, phase, and charge qubits. As a result, there is a substantial effort to understand the microscopic mechanisms that cause dephasing and to develop materials solution to eliminate the fluctuators. Most models for critical current fluctuations assume the existence of charge trapping centers within the insulating barrier and/or at the superconductor-insulator interface. In this talk we present critical-current noise characteristics of both diffused and epitaxially grown Nb/AlOx/Nb resistively shunted Josephson junctions. We compare the magnitude of 1/f critical-current noise to the ``universal'' value deduced from a compilation of noise measurements in junctions of different sizes and materials.
Supported by ARO and IARPA.- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2011
- Bibcode:
- 2011APS..MARP23012O