Multiband superconductivity and penetration depth in

Abstract

The effective superconducting penetration depth measured in the vortex state of PrOs4Sb12 using transverse-field muon spin rotation (TF-µSR) exhibits an activated temperature dependence at low temperatures, consistent with a nonzero gap for quasiparticle excitations. In contrast, Meissner-state radiofrequency (rf) inductive measurements of the penetration depth yield a T 2 temperature dependence, suggestive of point nodes in the gap. A scenario based on the recent discovery of extreme two-band superconductivity in PrOs4Sb12 is proposed to resolve this difference. In this picture a large difference between large-and small-gap coherence lengths renders the field distribution in the vortex state controlled mainly by supercurrents from a fully-gapped large-gap band. In zero field all bands contribute, yielding a stronger temperature dependence to the rf inductive measurements.

Field-dependent mass enhancement inPr1−xLaxOs4Sb12Zwicknagl1, Thalmeier2, Fulde3 2009Phys. Rev. B11180View full textAdd to dashboardCite

“…However, questions and ambiguities remain. They concern the experimental findings for the penetration depth [3,4] and initial studies of the thermal conductivity in a rotating magnetic field [5]. For example, the former suggest a possible nodal structure while the latter in addition points towards two distinct superconducting phases.…”

Muon spin rotation measurement of the magnetic field penetration depth inBa(Fe0.926Co0.074)

“…33 Multiband superconductivity has been proposed in many other materials, including CeCoIn 5 , 35,36 BaNi 2 P 2 , 37 and PrOs 4 Sb 12 . 38 We next fit the superfluid density to a phenomenological two-gap model 39,40 which has been employed in a previous SR study of LaFeAs͑O,F͒, Ca͑Fe,Co͒AsO, and ͑Ba, K͒Fe 2 As 2 41 n s ͑T͒ = n s ͑0͒ − w · ␦n s ͑⌬ 1 ,T͒ − ͑1 − w͒ · ␦n s ͑⌬ 2 ,T͒, ͑1͒…”

Inelastic quasiparticle scattering andT1−1NQR relaxation rate inPr1−xParker1, Thalmeier2 2008Phys. Rev. B6090View full textAdd to dashboardCite

“…Our has a slope of approximately six at T c as a result of the very strongcoupling nature of this material. For completeness, we also show the superfluid density obtained from the muon spin rotation data of MacLaughlin et al, 26 which shows somewhat different behavior near T c and at low temperature. Our prediction deviates from Chia's data mostly at low temperature, where it is exponentially activated, due to the small gap where ⌬͑k͒ has its minimum at approximately 0.25⌬ 0 .…”