Inhomogeneous magnetic multiband superconductors

TL;DR

This paper investigates how short-scale disorder affects the coexistence of superconductivity and spin-density-wave order in multiband metals, revealing that disorder broadens the coexistence region.

Contribution

It introduces a minimal two-band model with disorder to analyze the spatial inhomogeneity of order parameters using a quasiclassical approach.

Findings

Disorder causes spatial inhomogeneity in superconducting and magnetic order parameters.

Short-scale pairing disorder broadens the coexistence region.

The model encodes microscopic details in the correlation function of coupling fluctuations.

Abstract

We consider 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 develop spatial correlations. 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 consider a minimal model with two nested two-dimensional Fermi surfaces and disorder potentials which include both intra- and inter-band scattering. The model is analyzed using the quasiclassical approach to show that short-scale pairing-potential disorder leads to a broadening of the coexistence region.