Pseudogaplike feature of slightly underdoped (BaK)Fe$_{2}$As$_{2}$ studied by ultrafast spectroscopy

ORAL

Abstract

We have utilized ultrafast optical spectroscopy to study carrier dynamics in slightly underdoped (BaK)Fe$_{2}$As$_{2}$ crystals without magnetic transition. The photoelastic signals due to coherent acoustic phonons have been quantitatively investigated. According to our temperature-dependent results, we found that the relaxation component of superconducting quasiparticles persisted from the superconducting state up to at least 70 K in the normal state. Our findings suggest that the pseudogaplike feature in the normal state is possibly the precursor of superconductivity. We also highlight that the pseudogap feature of K-doped BaFe$_{2}$As$_{2}$ is different from that of other iron-based superconductors, including Co-doped or P-doped BaFe$_{2}$As$_{2}$.

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Authors

  • Kung-Hsuan Lin

    • Institute of Physics, Academia Sinica, Taipei, Taiwan

  • Kuan-Jen Wang

    • Institute of Physics, Academia Sinica, Taipei, Taiwan

  • Chung-Chieh Chang

    • Institute of Physics, Academia Sinica, Taipei, Taiwan

  • Yu-Chieh Wen

    • Institute of Physics, Academia Sinica, Taipei, Taiwan

  • B. Lv

    • Department of Physics, The University of Texas at Dallas, Richardson, TX, USA
    • Texas Center for Superconductivity, University of Houston

  • C. W. Chu

    • Texas Center for Superconductivity, University of Houston, Houston, TX, USA
    • TCSUH and Department of Physics, University of Houston
    • Texas Center for Superconductivity & Department of Physics, University of Houston, TX, USA
    • Texas Center for Superconductivity, University of Houston
    • TcSUH and Department of Physics, University of Houston, Lawrence Berkeley National Laboratory, Berkeley, CA

  • Maw-Kuen Wu

    • Institute of Physics, Academia Sinica, Taipei, Taiwan