APS Logo

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.

–

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