Manifestation of the multiband nature in the BCS-BEC crossover of FeSe<sub>1-<i>x</i></sub>S<i><sub>x</sub></i>

ORAL

Abstract

The crossover from the superconductivity of Bardeen-Cooper-Shrieffer (BCS) regime to Bose-Einstein condensation (BEC) regime holds the key to understanding the nature of pairing and condensation of fermions [1]. In electron systems in solids, however, it is generally difficult to control the paring strength of the electrons, and complete evidence of the BCS-BEC crossover has been elusive so far. Here, we provide the first example of complete evidence for the BCS-BEC crossover in an iron-based superconductor FeSe1-xSx from laser-excited angle-resolved photoemission spectroscopy, and propose a multiband mechanism for BCS-BEC crossover in this system.

[1] M. Randeria et al., Annu. Rev. Cond. Matt. Phys. 5, 209-232 (2014).

*This research is supported by Photon and Quantum Basic Research Coordinated Development Program of MEXT and partially supported by Grants-in-Aid for Scientific Research (KAKENHI) (Grant Numbers JP25220707, JP16K17741, JP25220710, JP15H02106, JP15H03688), and on Innovative Areas Topological Material Science (Grant Number JP15H05852) from Japan Society for the Promotion of Science (JSPS). T. H. acknowledges the JSPS Research Fellowship for Young Scientists (DC2).

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Presenters

  • Takahiro Hashimoto

    • Institute for Solid State Physics, University of Tokyo

Authors

  • Takahiro Hashimoto

    • Institute for Solid State Physics, University of Tokyo

  • Yuichi Ota

    • Institute for Solid State Physics, University of Tokyo

  • Akihiro Tsuzuki

    • Institute for Solid State Physics, University of Tokyo

  • Tsubaki Nagashima

    • Institute for Solid State Physics, University of Tokyo

  • Akiko Fukushima

    • Institute for Solid State Physics, University of Tokyo

  • Shigeru Kasahara

    • Department of Physics, Kyoto University
    • Dept. Phys., Kyoto Univ.
    • Kyoto Univ
    • Physics, Kyoto University
    • Kyoto University

  • Yuji Matsuda

    • Department of Physics, Kyoto University
    • Department of Physics, Kyoto Univ
    • Dept. Phys., Kyoto Univ.
    • Kyoto Univ
    • Physics, Kyoto University
    • Kyoto University

  • Kohei Matsuura

    • Univ of Tokyo
    • Department of Advanced Materials Science, University of Tokyo
    • Department of Advanced Materials Science, The University of Tokyo
    • Univ of Tokyo-Kashiwanoha

  • Yuta Mizukami

    • Department of Advanced Materials Science, University of Tokyo

  • Takasada Shibauchi

    • Advanced Materials Science, University of Tokyo
    • Univ of Tokyo-Kashiwanoha
    • Department of Advanced Materials Science, University of Tokyo
    • Univ of Tokyo
    • Dept. Adv. Mat. Sci., Univ. Tokyo
    • Univ. of Tokyo
    • Department of Advanced Materials Science, The University of Tokyo
    • Department of Advanced Material Science, University of Tokyo

  • Shik Shin

    • Univ of Tokyo
    • University of Tokyo
    • Institute for Solid State Physics, University of Tokyo
    • Univ of Tokyo-Kashiwanoha
    • Institute for Solid State Physics, The University of Tokyo

  • Kozo Okazaki

    • Institute for Solid State Physics, University of Tokyo
    • Univ of Tokyo-Kashiwanoha