Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 15: Superconductivity: Fe-based Superconductors - Other Materials and Theory

TT 15.4: Vortrag

Montag, 1. April 2019, 15:45–16:00, H23

Tracking nematic fluctuations using the Nernst effect in Co-doped LaFeAsO — •Christoph Wuttke¹, Federico Caglieris¹, Steffen Sykora¹, Frank Steckel¹, Xiaochen Hong¹, Seunghyun Kim¹, Rhea Kappenberger¹, Saicharan Aswartham¹, Sabine Wurmehl¹, Sheng Ran², Paul C. Canfield², Bernd Büchner^1,3,4, and Christian Hess^1,4 — ¹Leibniz-Institute for Solid State and Materials Research, IFW-Dresden, 01069 Dresden, Germany — ²Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA — ³Institut für Festkörperphysik, TU Dresden, 01069 Dresden, Germany — ⁴Center for Transport and Devices, Technische Universität Dresden, 01069 Dresden, Germany

We use the Nernst coefficient to track the nematic fluctuations through the Co-doped phase diagram of LaFeAsO. Similarly to our previous measurements in an 122-iron based superconductor system, we obtain a significant enhancement of the signal in the nematic fluctuation regime. The doping dependence of the Nernst coefficient exhibits a non-monotonic behavior featuring a local maximum in the vicinity of optimal doping. This peculiar doping dependence is also in agreement with our theoretical prediction and hence demonstrates the universality of the sensitivity of the Nernst effect on nematic fluctuations in iron based superconductors.