Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 27: SC: Fe-based Superconductors - LiFeAs
TT 27.6: Vortrag
Dienstag, 15. März 2011, 15:15–15:30, HSZ 304
Transport properties of LiFeAs — •Gerhard Kolland1, Oliver Heyer1, Stephanie Orbe1, Volodymyr Zabolotnyy2, Daniil Evtushinsky2, Sergiy Borisenko2, Igor Morozov2, Luminita Harnagea2, Sabine Wurmehl2, Christian Hess2, Bernd Büchner2, and Thomas Lorenz1 — 1II. Physikalisches Institut, Universität zu Köln, Germany — 2Leibniz-Institute for Solid State Research, IFW-Dresden, Germany
LiFeAs is unique among the broad family of FeAs-based superconductors, because it is the only stoichiometric
compound that is superconducting at a rather large Tc≃ 18 K under ambient conditions. We studied electrical and thermal
transport on high-quality single crystals.
The low-temperature resistivity shows quadratic temperature dependence above Tc
giving evidence for strong electron-electron scattering, while there is a tendency towards
saturation around room temperature. The Hall constant is negative and changes with temperature,
what most probably arises from a van Hove singularity close to the Fermi energy in one of the holelike
bands. From the anisotropic magnetic-feld dependence of Tc we extrapolate the correlation
lengths ξi and derive a moderate anisotropy ξa/ξc ≃ 2.2.
The thermal conductivity κ shows a shoulder below Tc. This feature is strongly
suppressed by an applied magnetic field whereas below 1 K the thermal conductivity
increases with increasing field.
Supported by the DFG through SFB 608 and SPP1458.