1. Condensed-Matter Physics & Materials Science Seminar

    "Mechanism as to why alcoholic beverages can induce superconductivity in FeTe1-xSx and FeTe1-xSex"

    Presented by Yoshihiko Takano, Yoshihiko Takano, Japan

    Monday, July 15, 2013, 10:30 am
    Bldg. 480 conference room

    Hosted by: Qiang Li

    FeTe is one of the parent compounds of Fe-based superconductors. It exhibits an antiferromagnetic ordering associated with a lattice distortion at 70 K. The partial S and Se substitutions suppress the low temperature structural/magnetic phase transition, and thereby induce superconductivity. At low substitution rate, only filamentary superconductivity is observed although the antiferromagnetic ordering seems to be suppressed. This is because that FeTe possesses excess Fe (~9 %) at the interlayer site. A previous report indicated that excess Fe supplies a substantial amount of electron to iron layer [1], and thus the physical properties of FeTe depend on the content of excess Fe. Therefore, to achieve bulk superconductivity in Fe-chalcogenide compounds, control of the excess Fe is required. So far, we have reported that the bulk superconductivity in the Fe-chalcogenides, FeTe1-xSex and FeTe1-xSx, is achieved by air exposure, oxygen annealing and alcoholic beverages immersing [1-5]. It was proposed that intercalated oxygen compensate the electron carrier of the excess Fe. Furthermore, it is revealed that hot commercial alcoholic beverages have the ability to deintercalate the excess Fe in the sample, and hence bulk superconductivity is achieved [6-7]. In this presentation, we reports details of our research on the Fe-chalcogenide superconductors. [