Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 52: Superconductivity: Fe-based Superconductors – FeSe and others
TT 52.5: Talk
Wednesday, March 18, 2015, 10:30–10:45, H 2053
Evidence for a pseudogap and charge density wave in FeSe — •Sahana Roessler1, Cevriye Koz1, Ulrich Schwarz1, Ulrich K. Roessler2, Frank Steglich1, Liu Hao Tjeng1, Peter Thalmeier1, and Steffen Wirth1 — 1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany — 2IFW Dresden, Postfach 270016, 01171 Dresden, Germany
We present scanning tunneling microscopy/spectroscopy (STM/S) and electrical transport measurements on the structurally simple Fe-based superconductor FeSe. This compound displays a structural transition at Ts = 90 K [1,2] and a superconducting transition at Tc = 8.5 K [3]. We show that there is a crossover energy scale at temperature T*≈ 70 K, below which the anisotropic scatterings of the quasiparticles dominate the transport. The magnetization measurements indicate that T* is also an energy scale of spin fluctuations. A pseudogap associated with a one-dimensional charge density wave (CDW) was observed below 35 K in the STM/S. The CDW is found to coexist with superconductivity. The pseudogap as well as the CDW observed here are reminiscent of behaviors found also in several high-Tc cuprates, strongly suggesting that the spin and charge fluctuations are intimately connected with high-temperature superconductivity.
[1] T. M. McQueen et al.,Phys. Rev. Lett. 103, 057002 (2009).
[2] C. Koz et al., Z. Anorg. Allg. Chem. 640, 1600-1606 (2014).
[3] F. C. Hsu et al., Proc. Natl. Acad. Sci. U. S. A. 105, 14262-14264 (2008).