Observation of anomalous temperature dependence of spectrum on small Fermi surfaces in a BiS$_2$-based superconductor

ORAL

Abstract

We have performed an angle-resolved photoemission spectroscopy study of the BiS2-based superconductor Nd(O,F)BiS$_2$. Two small electron-like Fermi surfaces around X ($\pi$, 0) are observed, which enclose 2.4\% and 1.1\% of the Brillouin zone area, respectively, corresponding to an electron doping of 7\% per Bi site. The low- energy spectrum consists of a weakly-dispersing broad hump and a dispersive branch, which follows well the calculated band dispersion. This hump is drastically suppressed with increasing temperature, while the dispersive branch is essentially unaffected. The anomalous thermal effect indicates a highly interacting electronic state, in which the superconducting pairing develops

*CAS (2010Y1JB6), MOST (2010CB923000, 2011CBA001000, 2011CB921701, 2013CB921700, 2011CBA00108, and 2012CB821403), NSFC (11004232, 11050110422, 11274362, 11234014, 11120101003, 11074291, 11274359, and 11104339), and DOE (DE-FG02-99ER45747 and DE-SC0002554).

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Authors

  • L.K. Zeng

    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences
    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • X.B. Wang

    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • J. Ma

    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • P. Richard

    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • S.M. Nie

    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • H.M. Weng

    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • N.L. Wang

    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • Z. Wang

    • Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA

  • T. Qian

    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • H. Ding

    • Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China