Direct evidence for Cooper pairing without a spectral gap in a disordered superconductor above T c

Science, vol. 374, pp. 608–611

Abstract

Measuring the effective charge At low enough temperatures, superconductors are capable of conducting electricity without any resistance because of the formation of so-called Cooper pairs of electrons. Cooper pairs typically form at the same critical temperature at which superconductivity sets in. In certain materials, they are thought to form above that temperature, but showing this property directly in an experiment is tricky. Bastiaans et al . used tunneling noise spectroscopy to measure the effective charge of current carriers in the disordered superconductor titanium nitride. As expected, below the critical temperature, the effective charge was equal to two electron charges. However, this behavior persisted above the critical temperature, indicating that electron pairs exist in that regime. —JS

Authors 12

1. Koen M. Bastiaans Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Physics, Leiden University, 2333 CA Leiden, Netherlands

2. Damianos Chatzopoulos Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Physics, Leiden University, 2333 CA Leiden, Netherlands

3. Jian-Feng Ge Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Physics, Leiden University, 2333 CA Leiden, Netherlands

4. Doo‐Hee Cho

   Yonsei University

   Affiliation as printed

   Department of Physics, Yonsei University, Seoul 03722, Republic of Korea

5. Willem O. Tromp Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Physics, Leiden University, 2333 CA Leiden, Netherlands

6. Jan M. van Ruitenbeek Aachen

   Leiden University

   Affiliation as printed

   Leiden Institute of Physics, Leiden University, 2333 CA Leiden, Netherlands

7. Mark H. Fischer

   University of Zurich

   Affiliation as printed

   Department of Physics, University of Zurich, 8057 Zurich, Switzerland

8. Pieter de Visser Aachen SRON Netherlands Institute for Space Research

   Space Research Organisation Netherlands

   Affiliation as printed

   SRON Netherlands Institute for Space Research, 2333 CA Leiden Netherlands

9. David J. Thoen

   Delft University of Technology

   Affiliation as printed

   Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, 2628 CD Delft, Netherlands

   Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands

10. E. F. C. Driessen

    Institut de Radioastronomie Millimétrique

    Affiliation as printed

    Institut de Radioastronomie Millimétrique (IRAM), Grenoble, 38400 Saint-Martin-d’Hères, France

11. T. M. Klapwijk

    University of Würzburg · Delft University of Technology

    Affiliation as printed

    Institute of Topological Materials, Julius-Maximilian-Universität Würzburg, 97070 Würzburg, Germany

    Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, Netherlands

12. Milan P. Allan corresponding Aachen

    Leiden University

    Affiliation as printed

    Leiden Institute of Physics, Leiden University, 2333 CA Leiden, Netherlands