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Title: Impact of iron-site defects on superconductivity in LiFeAs

In conventional s -wave superconductors, only magnetic impurities exhibit impurity bound states, whereas for an s ± order parameter they can occur for both magnetic and nonmagnetic impurities. Impurity bound states in superconductors can thus provide important insight into the order parameter. We present a combined experimental and theoretical study of native and engineered iron-site defects in LiFeAs. A detailed comparison of tunneling spectra measured on impurities with spin-fluctuation theory reveals a continuous evolution from negligible impurity-bound-state features for weaker scattering potential to clearly detectable states for somewhat stronger scattering potentials. Furthermore, all bound states for these intermediate strength potentials are pinned at or close to the gap edge of the smaller gap, a phenomenon that we explain and ascribe to multiorbital physics.
 [1] ;  [2] ;  [3] ;  [1] ;  [1] ;  [1] ;  [4] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [2]
  1. Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Physics and Astronomy, Quantum Matter Inst.
  2. Max Planck Inst. for Solid State Research, Stuttgart (Germany); Univ. of St. Andrews, Scotland (United Kingdom). School of Physics and Astronomy
  3. Max Planck Inst. for Solid State Research, Stuttgart (Germany)
  4. Univ. of Copenhagen (Denmark). The Niels Bohr Inst.
  5. Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy
  6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science, Computer Science and Mathematics Division
  7. Brookhaven National Lab. (BNL), Upton, NY (United States). Condensed Matter Physics and Materials Science Department (CMPMSD); Shanghai Jiao Tong Univ. (China). Dept. of Physics and Astronomy
  8. Univ. of Florida, Gainesville, FL (United States). Dept. of Physics
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC05-00OR22725; DMR-1407502
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 13; Journal ID: ISSN 2469-9950
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC); National Science Foundation (NSF)
Country of Publication:
United States