We study, analytically and numerically, phase locking of driven vortex lattices in fully frustrated Josephson junction arrays at zero temperature. We consider the case when an ac current is applied perpendicular to a dc current. We observe phase locking, steps in the current-voltage characteristics, with a dependence on external ac-drive amplitude and frequency qualitatively different from the Shapiro steps, observed when the ac and dc currents are applied in parallel. Further, the critical current increases with increasing transverse ac-drive amplitude, while it decreases for longitudinal ac drive. The critical current and the phase-locked current step width increase quadratically with (small) amplitudes of the ac drive. For larger amplitudes of the transverse ac signal, we find windows where the critical current is hysteretic, and windows where phase locking is suppressed due to dynamical instabilities. We characterize the dynamical states around the phase-locking interference condition in the current-voltage curve with voltage noise, Lyapunov exponents, and Poincaré sections. We find that zero-temperature phase-locking behavior in large fully frustrated arrays is well described by an effective four-plaquette model.

• Received 17 April 2003

DOI:https://doi.org/10.1103/PhysRevB.68.104521