Tunneling studies in a homogeneously disordered-wave superconductor: NbN
- 9 March 2009
- journal article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 79 (9)
- https://doi.org/10.1103/physrevb.79.094509
Abstract
We report the evolution of superconducting properties as a function of disorder in homogeneously disordered epitaxial NbN thin films grown on (100) MgO substrates, studied through a combination of electrical transport, Hall Effect and tunneling measurements. The thickness of all our films are >50nm much larger than the coherence length ~5nm. The effective disorder in different films encompasses a large range, with the Ioffe-Regel parameter varying in the range kFl~1.38-8.77. Tunneling measurements on films with different disorder reveals that for films with large disorder the bulk superconducting transition temperature (Tc) is not associated with a vanishing of the superconducting energy gap, but rather a large broadening of the superconducting density of states. Our results provide strong evidence of the loss of superconductivity via phase-fluctuations in a disordered s-wave superconductor.Comment: pdf file including figureKeywords
This publication has 32 references indexed in Scilit:
- Island formation in disordered superconducting thin films at finite magnetic fieldsPhysical Review B, 2008
- Nature of the superconductor–insulator transition in disordered superconductorsNature, 2007
- Inhomogeneous pairing in highly disordereds-wave superconductorsPhysical Review B, 2001
- Disorder and Quantum Fluctuations in Superconducting Films in Strong Magnetic FieldsPhysical Review Letters, 2001
- Role of Spatial Amplitude Fluctuations in Highly Disordered-Wave SuperconductorsPhysical Review Letters, 1998
- Superconductor-Insulator Transitions in the Two-Dimensional LimitPhysics Today, 1998
- Electron tunneling determination of the order-parameter amplitude at the superconductor-insulator transition in 2DPhysical Review Letters, 1992
- Onset of superconductivity in the two-dimensional limitPhysical Review Letters, 1989
- Tunneling Study of Superconductivity near the Metal-Insulator TransitionPhysical Review Letters, 1984
- Theory of dirty superconductorsJournal of Physics and Chemistry of Solids, 1959