Stability limits of flux states in two-band superconductor rings

This study explores transitions between states with different winding number in two-band superconducting rings. From the time-dependent Ginzburg-Landau equations for two-component superconductors, we apply linear instability theory and develop a semianalytical method that provides the critical flux for phase-slip occurrence. The developed method was applied to investigate how the critical flux depends on physical properties, such as band parameters and temperature. Finally, we show the possible existence of a soliton state, in which the phase winding number is different in each condensate.