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 ${\mathrm{MgB}}_2$, where they can result in oscillating and resistive switching effects.

Figure 1

Formation of phase textures in current-carrying bilayer. Thick black line shows the interlayer Josephson contact and gray rectangles show current leads.

Figure 2

Flux flow resistance $R(I)$ for the moving phase texture as a function of the current $I$ along the bilayer.