Dynamic phases of low-temperature low-current driven vortex matter in superconductors

Abstract

Using molecular dynamics simulations of vortices in a high-temperature superconductorwith square periodic arrays of pinning sites, dynamic phases of the low-current drivenvortices are studied at low temperatures. A rough vortex phase diagram of three distinctregimes of vortex flow is proposed. At zero temperature, we obtain a coupled-channelregime where rows of vortices flow coherently in the direction of the driving force.As the temperature is increased, a smooth crossover into an uncoupled-channelregime occurs where the coherence between the flowing rows of vortices becomesweaker. Increasing the temperature further leads to a plastic vortex regime, wherethe channels of flowing vortices completely disappear. The temperatures of thecrossovers between these regimes were found to decrease with the driving force.