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Large Ca Isotope Effect in CaC6

D. G. Hinks·D. Rosenmann·H. Claus·M. S. Bailey·J. D. Jorgensen
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Abstract

We have measured the Ca isotope effect in the newly discovered superconductor CaC6. The isotope effect coefficient is 0.50(7). If one assumes that this material is a conventional electron-phonon coupled superconductor, this result shows that the superconductivity is dominated by coupling of the electrons by Ca phonon modes and that C phonons contribute very little. Thus, in contrast to MgB2, where phonons in the B layers are responsible for the superconductivity, in CaC6 the phonons are primarily modes of the intercalated Ca.

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D. G. Hinks, D. Rosenmann, H. Claus, M. S. Bailey, J. D. Jorgensen. 2006-04-27. Large Ca Isotope Effect in CaC6. https://doi.org/10.1103/physrevb.75.014509

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