Superconductor Energy-Gap Symmetry Determination using Multi-Atom Quasiparticle Interference Imaging

ORAL

Abstract

A detailed knowledge of symmetry of superconducting gap Δα(k), for all momenta k on Fermi surface of each band α is required for a complete understanding of complex superconductors. Numerous techniques exist for determining |Δα(k)| but few to measure the sign of Δα(k). Recently, a new technique was introduced where energy- and phase-resolved Fourier analysis of quasiparticle interference images identifies whether the wavevectors connect Δα(k) of same-sign or opposite-sign. But the reliance on precise single impurity atom location for phase accuracy renders this technically difficult. We introduce a generalized technique which can be used with multiple impurities. We show its validity by comparing results of our technique with FeSe where s± Δα(k) symmetry is established. To exemplify utility, we apply our technique on LiFeAs and find that scattering interference between the hole- and electron-pockets indicates opposite sign.

*P.C.C. and A.B. acknowledge Ames lab United States Department of Energy DE-AC02-07CH11358. RS acknowledges NSF MRSEC program (DMR-1719875). P.J.H. and M.A.S. acknowledge NSF-DMR-1849751; J.C.S.D. acknowledges Moore Foundation’s EPiQS GBMF9457, Royal Society R64897, Science Foundation Ireland SFI 17/RP/5445 and from the European Research Council DLV-788932.

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Presenters

  • Rahul Sharma

    • Cornell University
    • Quantum Materials Center, University of Maryland; Laboratory of Atomic and Solid States Physics, Cornell University
    • University of Maryland, College Park

Authors

  • Rahul Sharma

    • Cornell University
    • Quantum Materials Center, University of Maryland; Laboratory of Atomic and Solid States Physics, Cornell University
    • University of Maryland, College Park

  • Andreas Kreisel

    • Universität Leipzig
    • Institute for Theoretical Physics, University of Leipzig
    • Institute for Theoretical Physics, Leipzig University
    • Institut für Theoretische Physik, Universität Leipzig
    • University of Leipzig

  • Miguel Antonio Sulangi

    • Department of Physics, University of Florida

  • Jakob Böker

    • Ruhr-Universität Bochum
    • Institut für Theoretische Physik, Ruhr-Universität Bochum; Institute of Physics, Kazan Federal University

  • Andrey Kostin

    • Cornell University
    • Laboratory of Atomic and Solid State Physics, Cornell University

  • Milan Allan

    • Leiden University
    • Leiden Institute of Physics, Leiden University

  • Hiroshi Eisaki

    • National Institute of Advanced Industrial Science and Technology (AIST)
    • National Institute of Advanced Industrial Science and Technology

  • Anna Boehmer

    • Karlsruhe Institute of Technology
    • Institute for Quantum Materials and Technology, Karlsruhe Institute of Technology; Ames Laboratory, U.S. Department of Energy

  • Paul C. Canfield

    • Ames Laboratory/Iowa State University
    • Department of Physics and Astronomy, Ames Laboratory, Iowa State University
    • Ames Laboratory, Iowa State University, Dept. of Physics and Astronomy, Ames
    • Ames Laboratory, U.S. Department of Energy; Department of Physics, Iowa State University

  • Ilya Eremin

    • Ruhr-Universität Bochum
    • Ruhr Univ Bochum
    • Institut für Theoretische Physik, Ruhr-Universität Bochum; Institute of Physics, Kazan Federal University

  • James C Davis

    • Cornell University
    • Department of Physics, University of Oxford
    • University College Cork
    • Laboratory of Atomic and Solid State Physics, Cornell University; Department of Physics, University College Cork; Max-Planck Institute for Chemical Physics of Solids; Clarend

  • Peter Hirschfeld

    • University of Florida
    • Department of Physics, University of Florida
    • Physics, University of Florida
    • univ of Florida

  • Peter Oliver Sprau

    • University of California, San Diego
    • Advanced Development Center, ASML
    • Advanced Development Center, ASML; Laboratory of Atomic and Solid State Physics, Cornell University