Dresden 2014 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 53: Superconductivity: Fe-based Superconductors - 122
TT 53.3: Vortrag
Mittwoch, 2. April 2014, 10:00–10:15, HSZ 201
Superconducting specific heat jump Δ C ∝ Tcβ (β ∼ 2) and gapless Fermi surfaces in K1−xNaxFe2As2 — •V. Grinenko1, D.V. Efremov1, S.-L. Drechsler1, S. Aswartham1, D. Gruner1, M. Roslova1, I. Morozov1, K. Nenkov1, S. Wurmehl1,2, A.U.B. Wolter1, B. Holzapfel1,3, and B. Büchner1,2 — 1Leibniz-Institute for Solid State and Materials Research, IFW-Dresden, D-01171 Dresden, Germany — 2Institut für Festkörperphysik, TU Dresden, Germany — 3Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
We present a systematic study of the electronic specific heat jump (Δ Cel) at the superconducting transition temperature Tc of K1−xNaxFe2As2. Both Tc and Δ Cel monotonously decrease with increasing x. The jump scales approximately with a novel power-law: Δ Cel ∝ Tcβ with β ≈ 2 determined by the impurity scattering rate. This finding is in sharp contrast to most of all iron-pnictide superconductors with a cubic Bud’ko-Ni-Canfield (BNC) scaling. Our observations, also, suggests that disorder diminishes the small gaps leading to partial gapless superconductivity which results in a large residual Sommerfeld coefficient in the superconducting state for x > 0. Both T-dependence of Cel(T) in the superconducting state and the nearly quadratic scaling of Δ Cel at Tc are well described by the Eliashberg-theory for a single-band d-wave superconductor with weak pair-breaking due to nonmagnetic impurities having reduced the density of superconducting quasi-particles.