Why is KC$_8$ superconductor and LiC$_6$ is not?

ORAL

Abstract

Superconductivity in graphite intercalated compound(GIC) has been studied for decades. Discovery of CaC$_6$ with $T_c = 11.5 K$ has resurged the intense study of GICs.Many GICs have been found to be superconducting with $T_c$ ranges from milikelvins to more than 10 kelvins, however there is not a clear trend. We performed a systematic angle resovled photoemission spectroscopy(ARPES) study on both KC$_8$ and LiC$_6$, the former is superconductor while the latter is not. We found a trend that superconductivity is correlated to electron phonon coupling and doping. Our result gives a natural explanation of why the KC$_8$ is superconductor and LiC$_6$ is not.

*This work was supported by the US Department of Energy and the UK Engineering and Physical Science Research Council

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Authors

  • T. Valla

    • Brookhaven National Laboratory

  • J. Camacho

    • Brookhaven National Laboratory

  • M.H. Upton

    • Argonne National Laboratory

  • Z.-H Pan

    • Brookhaven National Laboratory
    • Brookaven National Laboratory

  • A.V. Fedorov

    • Lawrence Berkeley National Laboratory

  • A.C. Walters

    • University College London

  • C.A. Howard

    • University College London

  • M. Ellerby

    • University College London