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TT: Fachverband Tiefe Temperaturen
TT 52: Superconductivity: Fe-based Superconductors - FeSe and LiFeAs
TT 52.8: Vortrag
Mittwoch, 14. März 2018, 11:30–11:45, HFT-FT 101
Structural component of an incipient ordering mode — •Sahana Roessler1, Alexander A. Tsirlin2, Marco Scavini3, Cevriye Koz1, Ulrich Schwarz1, Ulrich K. Roessler4, and Steffen Wirth1 — 1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany — 2Experimental Physics VI, University of Augsburg, Germany — 3Chemistry Department, University of Milan, Milano, Italy — 4IFW-Dresden, Institute for Solid State Research, D-01171 Dresden, Germany
The binary compound FeSe is a multiband superconductor with fascinating properties. Unlike other Fe-based superconductors, the transition from tetragonal (P4/nmm) to orthorhombic (Cmme) structure in FeSe at Ts ≈ 87 K at ambient pressure is not accompanied by a long-range magnetic order and the leading order parameter of the phase transition is attributed to an electronic origin. Upon further reducing temperature, two energy scales at temperatures T*≈ 75 K and T**≈ 20 K have been identified based on anomalies observed in the Hall effect, magnetotransport, thermal conductivity, and scanning tunneling spectroscopy [1]. Here we show, using a pair distribution function analysis, a local Fe-Fe atomic distortion with short-range correlations occurring at T**. Thus, incipient ordering in FeSe occurs as a precursor state to superconductivity and is reminiscent of behavior found in several high-Tc cuprates [2].
S. Rößler et al., Phys. Rev. B 92, 060505(R) (2015).
E. Fradkin and S. A. Kivelson, Nature Phys. 8, 864 (2012).