Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 52: Superconductivity: Fe-based Superconductors – FeSe and others
TT 52.7: Talk
Wednesday, March 18, 2015, 11:15–11:30, H 2053
FeSe nano-crystals on Bi2Se3(0001) — Sujit Manna1, Roozbeh Shokri1, Holger L. Meyerheim1, Sumalay Roy1, Katayoon Mohseni1, •Alberto Cavallin1, Vasilii Sevriuk1, Dirk Sander1, and Jürgen Kirschner1,2 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany — 2Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany.
Iron selenide (FeSe) is a prominent and intensely investigated bulk superconductor owing to its simple tetragonal structure and high transition temperature TC of 8.5 K [1]. Tremendous activity has aimed to increase TC by applying pressure, chemical doping, and by a reduction of the structural symmetry [2–4]. Here, we present our LEED, XRD, STM, and STS results on the epitaxial growth of few unit cells thick FeSe nano-crystals on the (0001) surface of the topological insulator Bi2Se3. In this case, the substrate induces a uniaxial in-plane strain and lowers the FeSe symmetry from tetragonal to orthorhombic with a b/a ratio of 1.02. STS at 10 K shows a differential conductivity gap at the Fermi energy. Our results open new perspectives for the study of Fe-based superconductivity and of superconductor/topological insulator interfaces in general, by identifying the role of epitaxial strain to modify the atomic structure of FeSe.
[1] F. C. Hsu, et al. Proc. Natl. Acad. Sci. USA 105, 14262 (2008).
[2] Y. Mizuguchi, et al. Applied Phys. Lett. 93, 152505 (2008).
[3] S. Medvedev, et al. Nature Materials 8, 630 (2009).
[4] Q.-Y. Wang, et al. Chin. Phys. Lett. 29, 037402 (2012).