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TT: Fachverband Tiefe Temperaturen
TT 19: Superconductivity: Poster Session
TT 19.15: Poster
Monday, March 7, 2016, 15:00–18:00, Poster D
Superfluid density and superconducting transition temperature in dirty iron-based superconductors — •Thomas Hartmann, Felix Ahn, and Ilya Eremin — Ruhr-Universität Bochum, Bochum, Deutschland
Measurements on optimally electron doped LaFeAsO1−xFx samples under pressure up to ∼23 kbar reveal a clear mutual independence between the critical temperature Tc and the ratio of superfluid density over effective band mass of Cooper pairs ns/m*. The ratio increases about ∼30 % at the maximum pressure whereas Tc remains constant, which clearly implies a breakdown of the Uemura relation in LaFeAsO1−xFx [1]. Here we analyze theoretically this effect by taking into account the effect of nonmagnetic impurities in a multi-band superconductor. We show that the ratio between intra-band and inter-band scattering rates can explain the behaviour of the observables under pressure by only acting on structural parameters while the amount of chemical disorder is still constant.
G. Prando et al., PRL 114, 247004 (2015)