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 “hexatic glass.” The simulated current-voltage characteristics are in excellent agreement with recent transport measurements on amorphous ${\mathrm{Mo}}_{77}{\mathrm{Ge}}_{23}$ thin film superconductors.