Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 21: Superconductivity: Poster Session
TT 21.27: Poster
Montag, 16. März 2015, 15:00–18:00, Poster B
Transport Properties of FeAs Single Crystals — •Matthias Gillig1, Seunghyun Khim1, Sabine Wurmehl1, 2, Bernd Büchner1, 2, and Christian Hess1, 3 — 1Institute for Solid State Research, IFW Dresden, 01069 Dresden, Germany — 2Technische Univeristät Dresden, 01069 Dresden, Germany — 3Center for Transport and Devices, Technische Universität Dresden, 01069 Dresden, Germany
The electronic properties of all FeAs-based superconductors are primarily determined by the electronic states of the FeAs layers in these compounds. The physical properties of binary compound FeAs are therefore of general interest, despite the different structure as compared to that of hypothetical isolated FeAs-layers in the superconducting compounds. More specifically, FeAs crystallizes in an orthorhombic structure containing distorted FeAs6 octahedra, instead of the FeAs4 tetrahedra of the layers in the superconductors.
We have performed transport measurements on FeAs single crystals along all crystallographic directions. The resistivity is only weakly anisotropic and possesses a temperature dependence with a positive slope but a rather unusual non-linear behaviour. For temperatures T 200 K the resistivity is only weakly temperature dependent up to room temperature. However, below ∼ 200 K the resistivity drops strongly upon cooling and exhibits a sharp kink at the spin density wave transition at ∼70 K, resembling the unusual normal state resistivity of many Fe-based superconductors.