Multi-atom quasiparticle scattering interference for superconductor energy-gap symmetry determination
Repository KITopen (Karlsruhe Institute of Technology)
Abstract
Complete theoretical understanding of the most complex superconductors requires a detailed knowledge of the symmetry of the superconducting energy-gap Δ$\frac{α}{k}$, for all momenta k on the Fermi surface of every band α. While there are a variety of techniques for determining |Δ$\frac{α}{k}$|, no general method existed to measure the signed values of Δ$\frac{α}{k}$. Recently, however, a technique based on phase-resolved visualization of superconducting quasiparticle interference (QPI) patterns, centered on a single non-magnetic impurity atom, was introduced. In principle, energy-resolved and phase-resolved Fourier analysis of these images identifies wavevectors connecting all k-space regions where Δ$\frac{α}{k}$ has the same or opposite sign. But use of a single isolated impurity atom, from whose precise location the spatial phase of the scattering interference pattern must be measured, is technically difficult. Here we introduce a generalization of this approach for use with multiple impurity atoms, and demonstrate its validity by comparing the Δ$\frac{α}{k}$ it generates to the Δ$\frac{α}{k}$ determined from single-atom scattering in FeSe where s± energy-gap symmetry is established. Finally, to exemplify utility, we use the multi-atom technique on LiFeAs and find scattering interference between the hole-like and electron-like pockets as predicted for Δ$\frac{α}{k}$ of opposite sign.
Authors 13
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Cornell University · Maryland Quantum Materials Center · University of Maryland, College Park
Affiliation as printed
Department of Physics, Cornell University, Ithaca, USA
Maryland Quantum Materials Center, Department of Physics, University of Maryland, College Park, USA
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Affiliation as printed
Institut für Theoretische Physik, Universität Leipzig, Leipzig, Germany
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Affiliation as printed
Department of Physics, University of Florida, Gainesville, USA
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Affiliation as printed
Institut für Theoretische Physik, Ruhr-Universität Bochum, Bochum, Germany
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Affiliation as printed
Department of Physics, Cornell University, Ithaca, USA
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Milan P. Allan Aachen
Affiliation as printed
Leiden Institute of Physics, Leiden University, Leiden, The Netherlands
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National Institute of Advanced Industrial Science and Technology
Affiliation as printed
National Inst. of Advanced Industrial Science and Tech., Tsukuba, Ibaraki, Japan
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Karlsruhe Institute of Technology · United States Department of Energy · Ames National Laboratory
Affiliation as printed
Ames Laboratory, U.S. Department of Energy, Ames, USA
Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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United States Department of Energy · Iowa State University · Ames National Laboratory
Affiliation as printed
Ames Laboratory, U.S. Department of Energy, Ames, USA
Department of Physics, Iowa State University, Ames, USA
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Kazan Federal University · Ruhr University Bochum
Affiliation as printed
Institut für Theoretische Physik, Ruhr-Universität Bochum, Bochum, Germany
Institute of Physics, Kazan Federal University, Kazan, Russian Federation
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J. C. Davis corresponding
Cornell University · University College Cork · University of Oxford · Max Planck Institute for Chemical Physics of Solids
Affiliation as printed
Clarendon Laboratory, University of Oxford, Oxford, UK
Department of Physics, Cornell University, Ithaca, USA
Department of Physics, University College Cork, Cork, Ireland
Max-Planck Institute for Chemical Physics of Solids, Dresden, Germany
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Affiliation as printed
Department of Physics, University of Florida, Gainesville, USA
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Affiliation as printed
Advanced Development Center, ASML, Wilton, USA
Department of Physics, Cornell University, Ithaca, USA
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