Spatially Inhomogeneous Magnetic Multiband Superconductors

We present the solution to a problem of superconductivity coexistence with the spin-density-wave order in disordered multiband metals. It is assumed that random variations of the disorder potential on short length scales render the interactions between electrons to become spatially correlated. As a consequence, both superconducting and magnetic order parameters become spatially inhomogeneous and are described by the universal phenomenological quantities, whereas all the microscopic details are encoded in the correlation function of the coupling strength fluctuations. We use a minimal model with two nested two-dimensional Fermi surfaces and disorder potentials which include both intra- and inter-band scattering. We use the quasiclassical approach to show that short-scale pairing-potential disorder leads to a broadening of the coexistence region. We also derive the expression for the exact T-matrix for our model and analyze the structure of the subgap states across the co-existence region.