Kim, H.Tanatar, M.A.Liu, YongSims, Zachary ColeZhang, ChenglinDai, PengchengLograsso, T.A.Prozorov, R.2017-06-052017-06-052014Kim, H., Tanatar, M.A., Liu, Yong, et al.. "Evolution of London penetration depth with scattering in single crystals of K1−xNaxFe2As2." <i>Physical Review B,</i> 89, no. 17 (2014) American Physical Society: https://doi.org/10.1103/PhysRevB.89.174519.https://hdl.handle.net/1911/94802London 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.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttps://doi.org/10.1103/PhysRevB.89.174519