On the mixed character of superconductivity fluctuations in two-band systems

• We examine the spatial variation of fluctuations in two-band superconductors.
• Critical and non-critical lengths scale the fluctuations and their correlations.
• The fluctuations appear as a mixture of critical and non-critical components.
• The ratio of these components depends on temperature and interband interaction.

We demonstrate that spatially inhomogeneous superconductivity fluctuations in both electron bands coupled via Josephson-type interaction consist of two components scaled by different characteristic lengths not related to the definite bands. Such mixed nature of fluctuations is a specific feature of two-gap superconductivity.