Insulating vortex cores in disordered superconductors

We show that while an orbital magnetic field and disorder, acting individually, weaken superconductivity, acting together they produce an intriguing evolution of a two-dimensional type-II s-wave superconductor. For weak disorder, the critical field Hc at which the superfluid density collapses is coincident with the field at which the superconducting energy gap gets suppressed. However, with increasing disorder these two fields diverge from each other, creating a pseudogap region with insulating vortex cores. Our results naturally explain two outstanding puzzles: the gigantic magnetoresistance peak observed as a function of magnetic field in thin disordered superconducting films and the disappearance of the celebrated zero-bias Caroli-de Gennes-Matricon peak in the local density of states at the vortex core in disordered superconductors.

Automated summary

We find that the presence of both an orbital magnetic field and disorder in a two-dimensional type-II s-wave superconductor leads to an intriguing evolution. As the disorder increases, the critical field for the collapse of superfluid density diverges from the field at which the superconducting energy gap is suppressed, creating a pseudogap region with insulating vortex cores. Our findings provide a natural explanation for the observed gigantic magnetoresistance peak in disordered superconducting films and the disappearance of the celebrated zero-bias Caroli-de Gennes-Matricon peak in the local density of states at vortex cores in disordered superconductors.