Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 52: Superconductivity: Fe-based Superconductors – FeSe and others
TT 52.8: Vortrag
Mittwoch, 18. März 2015, 11:30–11:45, H 2053
Mutual independence of Tc and superfluid density under pressure in optimally-doped LaFeAsO1−xFx — Giacomo Prando1, •Ilya Eremin2, Wolf Schottenhamel1, Zurab Guguchia3, Felix Ahn2, Thomas Hartmann2, Igor Nekrasov4, Rustem Khasanov3, Samuele Sanna5, Christian Blum1, Sabine Wurmehl1,6, and Bernd Büchner1,6 — 1Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden, D-01171 Dresden, Germany — 2Institut für Theoretische Physik III, Ruhr-Universität Bochum, D-44801 Bochum, Germany — 3Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland — 4Institute for Electrophysics, RAS, Ekaterinburg, 620016, Russia — 5Dipartimento di Fisica e Unitá CNISM di Pavia, Universitá di Pavia, I-27100 Pavia, Italia — 6Institut für Festkörperphysik, Technische Universität Dresden, D-01062 Dresden, Germany
We report on the effect of nearly-hydrostatic pressure P ≤ 23 kbar in an optimally-doped LaFeAsO1−xFx sample. Our results of muon spin rotation show no dependence of Tc on P and, at the same time, a remarkable enhancement of the superfluid density (ns). This is a dramatic effect, the saturation value of ns being increased by ∼ 30 % at the maximum P value. We provide evidence from density-functional theory (DFT) calculations that this increase should not be associated to an induced change in the fermiology of LaFeAsO1−xFx. Accordingly, we suggest that the experimental data can be explained by assuming a modification of the ratio between intra- and inter-band impurity scattering, only possible in multi-band SC.