Phase Textures Induced by dc-Current Pair Breaking in Weakly Coupled Multilayer Structures and Two-Gap Superconductors

We predict the current-induced formation of equilibrium phase textures for a multicomponent superconducting order parameter. Using the two-component Ginzburg-Landau and Usadel equations, we show that, for weakly coupled comoving superconducting condensates, the dc current I first causes the breakdown of the phase-locked state at I>I_c1 followed by the formation of intrinsic phase textures well below the depairing current I_d. These phase textures can manifest themselves in multilayer structures, atomic Bose condensate mixtures in optical lattices, and two-gap superconductors, particularly MgB₂, where they can result in oscillating and resistive switching effects.