Dynamics of domain walls in a Fulde–Ferrell superconductor

The mechanism of switching between different states of a quasi-one-dimensional current-carrying superconductor in the Fulde–Ferrell phase has been theoretically studied. It has been shown within the time-dependent Ginzburg–Landau model that switching at a current above a critical value occurs due to the appearance of finite domains with a nonzero electric field at the interface with a normal metal or in a “weak” place inside the superconductor and their motion along the superconductor. It has been found that each such soliton of the electric field corresponds to a moving domain wall that separates the parts of the superconductor with opposite directions of supervelocities and near which the absolute value of the superconducting order parameter is finite. The last property distinguishes such solitons from other well-known solitons in current-carrying superconductors, namely, moving Abrikosov or Josephson vortices.