Phase fluctuations in a strongly disordered s-wave superconductor close to the metal-insulator transition

Abstract

We explore the role of phase fluctuations in a 3-dimensional s-wave superconductor, NbN, as we approach the critical disorder for the destruction of the superconducting state. Scanning tunneling spectroscopy measurements reveal that in the presence of strong disorder, a finite gap in the electronic spectrum continues to persist at temperatures above Tc. With increase in disorder, the superfluid density is strongly suppressed at low temperatures and evolves towards a linear-T variation at higher temperatures. These observations provide strong evidence that phase fluctuation leads to the formation of a pseudogap state in a disordered conventional superconductor.

Minor modifications and figures. (pdf file with figure)

References in corpus (8)

• Nature of the superconductor-insulator transition in disordered superconductors
• Disorder-Induced Inhomogeneities of the Superconducting State Close to the Superconductor-Insulator Transition
• Eigenfunction fractality and pseudogap state near superconductor-insulator transition
• Superconducting properties and Hall Effect of epitaxial NbN thin films
• Tunneling studies in a homogeneously disordered s-wave superconductor: NbN
• Temperature dependence of resistivity and Hall-coefficient in a strongly disordered metal: NbN
• Phase diagram and upper critical field of homogenously disordered epitaxial 3-dimensional NbN films
• Fluctuations and $T_c$ reduction in cuprate superconductors

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• Optical signatures of the superconducting Goldstone mode in granular aluminum: experiments and theory
• Phase diagram and upper critical field of homogenously disordered epitaxial 3-dimensional NbN films
• High field termination of a Cooper-pair insulator
• Superconducting Energy Scales and Anomalous Dissipative Conductivity in Thin Films of Molybdenum Nitride
• Superconducting fluctuations in a thin NbN film probed by the Hall effect
• Slowing down of vortex motion in thin NbN films near the superconductor-insulator transition
• Dynamic transition from Mott-like to metal-like state of the vortex lattice in a superconducting film with a periodic array of holes
• Mesoscopic fluctuations of the local density of states in interacting electron systems