Dynamical Phase Transition in a Driven Disordered Vortex Lattice.

Using Langevin dynamics, we have investigated the dynamics of vortices in a disordered two-dimensional superconductor subjected to a uniform driving current. The results provide direct numerical evidence for a dynamical phase transition between a plastic flow regime and a moving {open_quote}{open_quote}hexatic glass.{close_quote}{close_quote} The simulated current-voltage characteristics are in excellent agreement with recent transport measurements on amorphous Mo{sub 77}Ge{sub 23} thin film superconductors. {copyright} {ital 1996 The American Physical Society.}