Magnetic penetration depth in disordered iron-based superconductors

Abstract

We study the effect of disorder on the London penetration depth in iron-based superconductors. The theory is based on a two-band model with quasi-two-dimensional Fermi surfaces, which allows for the coexistence region in the phase diagram between magnetic and superconducting states in the presence of intraband and interband scattering. Within the quasiclassical approximation we derive and solve Eilenberger's equations, which include a weak external magnetic field, and provide analytical expressions for the penetration depth in the various limiting cases. A complete numerical analysis of the doping and temperature dependence of the London penetration depth reveals the crucial effect of disorder scattering, which is especially pronounced in the coexistence phase. The experimental implications of our results are discussed.

Short-range antiferromagnetic correlations in the superconducting state of filled skutterudite alloys Pr1−xEuxPt4Ge12

“…conductors with magnetic impurities [25], multiband s ± superconductors with potential impurities with Γ being the interband scattering rate [3,26], and last, but not least, d-wave superconductors with nonmagnetic impurities [27][28][29]. The expression (2) describes the data quite well which is not surprising in light of the facts that the superconducting order parameter on one of the bands is nodal, while the pairing amplitudes on the other bands are nodeless [10].…”

Quasiclassical Theory of C4-Symmetric Magnetic Order in Disordered Multiband Metals

“…Having accomplished that goal, we can now generalize it to investigate the problem of an interplay between superconductivity and magnetism. It is already well-established that by including the interband disorder scattering Anderson-Abrikosov-Gor'kov theorem makes it possible for superconductivity and magnetism to co-exist in a certain region of the phase diagram, which size is determined by the ratio of the intra-and inter-band scattering rates [22,23]. The question is then would be to check if superconducting order may provide an additional contribution in determining which of the two competing magnetic states would be energetically favorable.…”

“…where x a is one of the roots of Equation (23). It is a priori not clear which one of the three roots must be chosen.…”

Anomalous Hall effect on the surface of topological Kondo insulators

“…When the impurity potential is short ranged on the scale of a, the matrix W K,K = n imp |u(0)| 2 for all K, K . The experimental analysis of the weak-antilocalization effect [41] in SmB 6 samples [14,20] suggests that this limit is most important for present day experiments. The explicit formula of σ xy ( /m, Γ /m) for the case v Γ = v, and m Γ = m has been relegated to Ref.…”