  Crystal plasticity occurs by deformation bursts due to the avalanche-like
motion of dislocations. Here we perform extensive numerical simulations of a
three-dimensional dislocation dynamics model under quasistatic
stress-controlled loading. Our results show that avalanches are power-law
distributed, and display peculiar stress and sample size dependence: The
average avalanche size grows exponentially with the applied stress, and the
amount of slip increases with the system size. These results suggest that
intermittent deformation processes in crystalline materials exhibit an extended
critical-like phase in analogy to glassy systems, instead of originating from a
non-equilibrium phase transition critical point.
