Melting of the moving vortex lattice in the presence of disorder

The authors investigate the melting of the two-dimensional vortex lattice moving in an inhomogeneous environment under the applied current j. They predict the existence of a dynamic phase transition at some current j = jt (crystallization current) from the motion of the amorphous configuration at j < jt to the motion of the crystal at j > jt. jt exceeds essentially the critical current jc for strongly disordered systems and approaches jc with the decrease of the degree of disorder. They find that jt diverges as temperature approaches the melting temperature of the undisturbed lattice