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 ${\rm Mo_{77}Ge_{23}}$ thin film superconductors. 
Seungoh Ryu, M. Hellerqvist, S. Doniach, A. Kapitulnik, D. Stroud