Large-scale spatial inhomogeneities in a long Josephson junction, where fluxons may be trapped, allow the existence of stable periodic dynamical regimes locked to the external frequency or twice this frequency, and biased with a very weak external current. These regimes lead to an abrupt cutoff located at the bottom of the zero-field step in the corresponding current-voltage characteristics. Such an easily detectable effect strongly suggests an experimental verification of this phase-locked soliton dynamics.

• Received 25 April 1988

DOI:https://doi.org/10.1103/PhysRevB.38.11284