Probing the Berezinskii-Kosterlitz-Thouless transition in two-dimensional superconductors using noise magnetometry

ORAL

Abstract

The Berezinskii-Kosterlitz-Thouless (BKT) transition is an exotic phase transition which occurs in two-dimensional systems and is characterized by the spontaneous proliferation of topological defects (vortices) above a critical temperature. While two-dimensional superconductors, including moirė and high-Tc superconductors, should in principle undergo such a BKT transition, it is often hard to conclusively demonstrate the presence of BKT physics using bulk DC transport alone. Here we will show how, using diamond nitrogen-vacancy (NV) center noise magnetometry, the precise details and dynamics of the BKT transition in superconductors could be fully characterized by studying the magnetic noise scaling with temperature, sample-depth, and frequency. A key prediction is that the magnetic noise will exhibit a nonmonotonic temperature and sample-depth dependence just above the BKT transition, providing a clear experimental signature. We also find that there is a clear qualitative difference between the magnetic noise produced by moving vortices and that which would result from Gaussian superconducting fluctuations, further demonstrating the power of noise magnetometry for probing two-dimensional superconductivity. We conclude by showing a wide variety of two-dimensional superconductors for which this technique is experimentally feasible given current constraints.

* This material is based upon work supported by the U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Quantum Science Center.

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Presenters

  • Jonathan B Curtis

    UCLA, University of California, Los Angeles

Authors

  • Jonathan B Curtis

    UCLA, University of California, Los Angeles

  • Nicholas R Poniatowski

    Harvard University

  • Pavel Dolgirev

    Harvard University

  • Nikola Maksimovic

    Harvard University

  • Amir Yacoby

    Harvard University

  • Bertrand I Halperin

    Harvard University

  • Prineha Narang

    College of Letters and Science, University of California, Los Angeles (UCLA), CA, USA., University of California Los Angeles, College of Letters and Science, University of California, Los Angeles (UCLA), UCLA, University of California, Los Angeles, College of Letters and Science, University of California, Los Angeles, Harvard University

  • Eugene Demler

    ETH, ETH Zurich, ETH Zürich, Institute for Theoretical Physics, ETH Zürich, 8093, Zürich, Switzerland