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Title: Electron doping evolution of the neutron spin resonance in NaFe 1-xCo xAs

Neutron spin resonance, a collective magnetic excitation coupled to superconductivity, is one of the most prominent features shared by a broad family of unconventional superconductors including copper oxides, iron pnictides, and heavy fermions. In this paper, we study the doping evolution of the resonances in NaFe 1–xCo xAs covering the entire superconducting dome. For the underdoped compositions, two resonance modes coexist. As doping increases, the low-energy resonance gradually loses its spectral weight to the high-energy one but remains at the same energy. By contrast, in the overdoped regime we only find one single resonance, which acquires a broader width in both energy and momentum but retains approximately the same peak position even when T c drops by nearly a half compared to optimal doping. Furthermore, these results suggest that the energy of the resonance in electron overdoped NaFe 1–xCo xAs is neither simply proportional to T c nor the superconducting gap but is controlled by the multiorbital character of the system and doped impurity scattering effect.
 [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [2] ;  [3] ;  [4] ;  [1] ;  [5] ;  [6]
  1. Rice Univ., Houston, TX (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
  4. Rice Univ., Houston, TX (United States); Beijing Normal Univ., Beijing (China)
  5. Normal Univ., Beijing (China)
  6. National Institute of Standards and Technology, Gaithersburg, MD (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC05-00OR22725; SC0012311
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 93; Journal Issue: 17; Journal ID: ISSN 2469-9950
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States