Abstract
A detailed numerical study of a sine-Gordon model of the Josephson tunnel junction is compared with experimental measurements on junctions with different ratios. The soliton picture is found to apply well on both relatively long () and intermediate () junctions. We find good agreement for the current-voltage characteristics, power output, and for the shape and height of the zero-field steps (ZFS). Two distinct modes of soliton oscillations are observed: (i) a bunched or congealed mode giving rise to the fundamental frequency on all ZFS's and (ii) a "symmetric" mode which on the ZFS yields the frequency Coexistence of two adjacent frequencies is found on the third ZFS of the longer junction () in a narrow range of bias current as also found in the experiments. Small asymmetries in the experimental environment, a weak magnetic field, e.g., is introduced via the boundary conditions of our numerical model. This gives a junction response to variations in the applied bias current close to that observed experimentally.
- Received 17 November 1981
DOI:https://doi.org/10.1103/PhysRevB.25.5737
©1982 American Physical Society