Figure 3: Effect of electron irradiation on the low-temperature penetration depth in BaFe2(As1−xPx)2 single crystals.
From: Disorder-induced topological change of the superconducting gap structure in iron pnictides
(a,b) Change in the magnetic penetration depth Δλ plotted against (T/Tc)2 for the same Tc0=28 K samples as Fig. 2a (a) and for the Tc0=29 K samples as Fig. 2b (b). The same colours are used as Fig. 2a,b for the corresponding irradiated doses. Each curve is shifted vertically for clarity. Lines are the T2 dependence fits at high temperatures. (c,d) Temperature dependence of Δλ for sample #28B with 2.0 C cm−2 (c) and for sample #29C with 2.7 C cm−2 (d). Red lines are the fits to the exponential dependence expected in fully gapped superconductors. (e) Temperature dependence of Δλ for sample #29A before (red) and after irradiation (blue) of 4.9 C cm−2 dose. Inset is an expanded view at the lowest temperatures.
