Superconductivity in C6Ca

Matteo Calandra; Francesco Mauri

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Superconductivity in C6Ca

Matteo Calandra·Francesco Mauri

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Abstract

Using density functional theory we demonstrate that superconductivity in C6Ca is due to a phonon-mediated mechanism with electron-phonon coupling 0.83 and phonon-frequency logarithmic-average 24.7 meV. The calculated isotope exponents are 0.24 for Ca and 0.26 for C. Superconductivity is mostly due C vibrations perpendicular and Ca vibrations parallel to the graphite layers. Since the electron-phonon couplings of these modes are activated by the presence of an intercalant Fermi surface, the occurrence of superconductivity in graphite intercalated compounds requires a non complete ionization of the intercalant.

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Matteo Calandra, Francesco Mauri. 2005-06-04. Superconductivity in C6Ca. https://arxiv.org/abs/cond-mat/0506082

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