Tunable impurity states in the unconventional superconductor FeTe<sub>0.55</sub>Se<sub>0.45</sub>

ORAL

Abstract

When a single impurity interacts with an unconventional superconductor, localized bound states appear inside its superconducting gap. Interestingly, these states can be used as a tool to bring insight into the electronic states of the material at stake. In this study, we use a low temperature scanning tunneling microscope operating at ultra-high vacuum, to find impurity states in the iron-based unconventional superconductor FeTe0.55Se0.45 (Tc=14.5 K). In order to enhance the energy resolution, a superconducting tip (Pb-coated) was employed. We find that the energy of the states shifts spatially and can be tuned by changing the distance between the sample and our scanning probe at the impurity site. In this talk I will discuss possible mechanisms that can lead to this dispersive behavior of the impurity energy state in space.

*Leiden University, NWO, NanoFront, ERC

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Presenters

  • Damianos Chatzopoulos

    • Leiden University

Authors

  • Damianos Chatzopoulos

    • Leiden University

  • Doohee Cho

    • Leiden University

  • Koen M Bastiaans

    • Leiden University

  • Genda Gu

    • Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory
    • Brookhaven national lab
    • Condensed Matter Physics and Materials Science, Brookhaven National Laboratory
    • Brookhaven National Lab
    • Condensed Matter Physics and Material Science, Brookhaven National Laboratory, Upton, NY, United States
    • Brookhaven National Laboratories
    • Condensed Matter Physics and Material Science Division, Brookhaven National Laboratory

  • Milan P. Allan

    • Leiden University