Figure 4: Theoretical calculations of impurity effects in iron-based superconductors.
From: Disorder-induced topological change of the superconducting gap structure in iron pnictides
(a) Schematic of possible s± and s++ states. Large circles and small ellipsoids (black lines) are hole and electron Fermi surfaces, respectively. Red and blue represents the superconducting order parameter with different signs. (b) Schematic of s± order parameter versus azimuthal angle φ (top row) and density of states N versus energy ω (bottom row) with increasing irradiation dosage (from left to right). Dotted lines (top row) are zero lines. (c) Density of states at Fermi level N(0) for nodal band plotted as false colour versus inter to intraband scattering ratio α and irradiation-induced residual resistivity Δρ0 for the model defined in the study by Wang et al.16 (d) Penetration depth change Δλ versus reduced temperature T/Tc for different values of Δρ0 as marked in legend, and inter to intraband scattering ratio α=0.6 (arrows in c). Each curve is shifted vertically for clarity.
