Dynamical phase transition in a fully frustrated Josephson array on a square lattice

We study dynamical phase transitions at temperature T=0 in-a fully, frustra ted square Josephson junction array subject to a driving current density, w hich has nonzero components i(x), i(y) parallel to both axes of the lattice . Our numerical results show clear evidence for three-dynamical phases: a p inned vortex lattice characterized by zero time-averaged voltages [v(x)](t) and [v(y)](t), a "plastic'' phase in which both [v(x)](t) and [v(y)](t) ar e nonzero, and a moving lattice phase in which only one of the:time-average voltage components is nonzero. The last of these has a finite transverse c ritical current. if a current is applied in the x direction, a nonzero tran sverse current density i(y) is required before [v(y)](t) becomes nonzero. T he voltage traces in the moving lattice phase are periodic in time. By cont rast, the voltages in the plastic phase have continuous power spectra that are weakly dependent on frequency. This phase diagram is found numerically to be qualitatively unchanged by the presence of weak disorder. We also des cribe two simple analytical models that recover some, but not all, the char acteristics of the three dynamical phases, and of the phase diagram calcula ted numerically. [S0163-1829(99)03345-7].