Intrinsic charge dynamics in high-<i>T</i><sub>c</sub> <i>A</i>FeAs(O,F) superconductors

ORAL

Abstract

We report the first determination of the in-plane complex optical conductivity of 1111 high-Tc superconducting iron oxypnictide single crystals PrFeAs(O,F) and thin films SmFeAs(O,F) by means of conventional and micro-focused infrared spectroscopy, ellipsometry, and time-domain THz transmission spectroscopy. A strong itinerant contribution is found to exhibit a dramatic difference in coherence between the crystal and the film. Using extensive temperature-dependent measurements of THz transmission we identify a previously undetected 2.5-meV collective mode in the optical conductivity of SmFeAs(O,F), which is strongly suppressed at Tc and experiences an anomalous T-linear softening and narrowing below T*≈110K»Tc. The suppression of the infrared absorption in the superconducting state reveals a large optical superconducting gap with a similar gap ratio 2Δ/kBTc≈7 in both materials, indicating strong pairing.

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Presenters

  • Aliaksei Charnukha

    • Department of Physics, Univ of California - San Diego
    • Physics, University of California San Diego

Authors

  • Aliaksei Charnukha

    • Department of Physics, Univ of California - San Diego
    • Physics, University of California San Diego

  • Daniel Pröpper

    • Solid-state spectroscopy, Max Planck Institute for Solid-State Research

  • N. Zhigadlo

    • Chemistry and Biochemistry, University of Bern

  • Michio Naito

    • Applied Physics, Tokyo University of Agriculture and Technology

  • Michael Schmidt

    • Experimental Physics V, University of Augsburg

  • Zhe Wang

    • Experimental Physics V, University of Augsburg

  • Joachim Deisenhofer

    • Experimental Physics V, University of Augsburg

  • Alois Loidl

    • Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg
    • Experimental Physics V, University of Augsburg

  • Bernhard Keimer

    • Max Planck Institute for Solid State Research
    • Max-Planck-Institut für Festkörperforschung
    • Solid-state spectroscopy, Max Planck Institute for Solid-State Research

  • Alexander Boris

    • Max Planck Institute for Solid State Research
    • Solid-state spectroscopy, Max Planck Institute for Solid-State Research

  • Dimitri Basov

    • Physics, University of California San Diego