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Title: Evolution of London penetration depth with scattering in single crystals of K1-xNaxFe2As2

London penetration depth, λ(T), was measured in single crystals of K1-xNaxFe2As2, x=0 and 0.07, down to temperatures of 50 mK, ~Tc/50. Isovalent substitution of Na for K significantly increases impurity scattering, with ρ(Tc) rising from 0.2 to 2.2 μΩ cm, and leads to a suppression of Tc from 3.5 to 2.8 K. At the same time, a close to T-linear Δλ(T) in pure samples changes to almost T2 in the substituted samples. The behavior never becomes exponential as expected for the accidental nodes, as opposed to T2 dependence in superconductors with symmetry imposed line nodes. The superfluid density in the full temperature range follows a simple clean and dirty d-wave dependence, for pure and substituted samples, respectively. This result contradicts suggestions of multiband scenarios with strongly different gap structure on four sheets of the Fermi surface.
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  1. Ames Laboratory
  2. University of Tennessee
  3. Rice University
Publication Date:
OSTI Identifier:
Report Number(s):
IS-J 8375
Journal ID: ISSN 1098-0121; PRBMDO; ArticleNumber: 174519
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 89; Journal Issue: 17
American Physical Society (APS)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States